general configuration questions.

1) Laptops in general are not really upgradeable in the desktop sense.
Since the MB is not upgradeable, you become very limited in what you can do.
The ram size and speed limits are set for life b/c of this. although changing ram to reach the MB limits is trivial. Harddrive swaps are trivial also.
In General, laptop cpu upgrades are not the norm. Yes it can be done, but this generally takes alot more experience than say a ram or hdd swap. But in general the MB limitation applies to Processors too, they usually accept a certain family of processors, that you can upgrade to the max of the family, but in laptops, socket compatability doesnt mean as much as w/ desktops due to a generally locked FSB and more restricted bios. Upgradeing outside of the target processor family is usually not a real possibility. AW is a unique company as it is one a a select few to offer upgradeable grafix. While this can be done, there is not a wide open laptop grfx card market as on the desktop. So you may get lucky to see 1-2 generations of new grfx offered and supported during the lifetime of a laptop, again the company support is important due to motherboard and bios restrictions that are the norm for laptops. Just b/c a mobile grfx card might fit in, there is no guaruntee it will work without company support. And with bot proc and grfx there are always power and thermal issues that have to be accounted for that are not really a factor in desktops.

2) In general AW is as stable as any other laptop, they traditionally use higher end name brand parts, and have personal care of building and testing that most other companies dont do.

3) The proc is the shit! while not the highest end model, the one you listed is from the family of the current flagship of high end mobile proc's. The ram is weak at ddr2 667 but the Santa Rosa chip set is a year old. In a month, montevina will be released with 1067 ffsb and 1067ddr3 ram. But it will be 2-3 months b4 those start showing up in customers hands, and no word from AW if they are going to support it. Untill then, the proc/ram specs you posted are the cream of the crop for laptops, and actually blow all but the higher end desktops away.

Your not understanding correctly!

That Sager uses a desktop proc, not a mobile one.
Side by side plugged into a wall your you will generate a better synthetic benchmark score that is CPU bound. Thats all.

Real world performance difference will only be seen shaving off minutes encoding an HD movie or the like.

What you give up though is immense: The desktop proc draws more wattage and runs hotter. So the laptop will run hotter and drain your battery faster. The laptop will be bigger and heavier to accommodate a more robust cooling system, and a larger battery that lasts under an hour sitting idle.

Real world gaming performance will be gpu bound which AW has the same (or better than) as the sager. Which means that extra desktop horsepower will be going to waste.

In the end is it technically a more powerful system, yes, but not by nearly as much as you seem to think, and the trade-offs you gave up for a mobile processor are large and many.

1. Laptops are somewhat upgradeable, but not as upgradeable as desktops. You can change out the memory easily in most notebooks. The hard drive is generally pretty easy to change out as well. Upgrading processors is also doable, but can be more difficult depending on the layout of the notebook. Video cards are almost never upgradeable and motherboards are absolutely never upgradeable.

2. Unlike desktop computers, the company that makes the chassis also makes the motherboard and determines the configuration. These companies are called original design manufacturers or ODMs for short. Alienware contracts with different ODMs for different models. For instance, I believe the ODM for the M15X is Arima, which means that the motherboard and chassis are designed and manufactured by Arima. I don't know who AW buys their memory or hard drives from, so I can't answer that question.

3. Since notebooks need to run within certain power and thermal limits that desktops don't, the best notebook components will always be at least a little behind the best desktop components. The T9300 is currently Intel's best mobile CPU for under $400. There are faster ones out, but they cost a LOT more. Also, the RAM speed is regulated by the chipset, and the latest Intel mobile chipset only supports DDR2 RAM up to 667 Mhz. As archalien said, this will change in June or so when Intel releases their next mobile chipset, but notebook RAM still won't be able to approach the current 1333 Mhz max (default) speed of desktop RAM, and notebook RAM cannot be overclocked.

According to the Notebook Check Benchmark List, the dual 8700s score around 3% better in 3DMark01, 24% better in 3DMark03, 5% better in 3DMark05, and 19% better in 3DMark06. It's not a huge performance increase. However, there IS a distinct performance increase if you compare the 8800M GTX SLI to either of the other graphics card options (compared to the 8700M SLI, it scored 20% better in 3DMark01, 77% better in 3DMark03, 26% in 3DMark05, and 51% better in 3DMark06)

No! You do that by hooking up a cable to the HDMI connector of the notebook. A TV tuner means that you can watch TV on the notebook.
Turbo Memory is an additional 1GB of flash storage on your motherboard that you can't actually use as storage but that Windows Vista can use to speed up hard drive access time. It's up to you whether you want it or not.

Unfortunately, especially notebooks gaming performance comes at a steep price. Some cost saving measures to help you achieve your goal......

First off if you really want a gaming notebook there is no way to get around the fact that you'll want/need the dual 8800's, you can game on the lower cards but as my esteemed colleague pointed out, the 8800's are really WAY more powerful and will help you push a much higher res on higher settings.

So its really important in my and most opinion to go balls out on the grfx cards and manage the price elsewhere. I also would stay with the 9300 proc as it is the price/performance champ right now.

Keep in mind that these are mobile versions of the grfx cards, as such they are in no way comparable to the power of their desktop counterparts.

So then how do you save money..... (Ram and Hdd)
Right now AW upgrade to 4g ram is 350$, you can buy 4gigs of better ram than AW installs from say Newegg, for like 200$ That saves you 150$ plus you can also delay this cost by not upgradeing for a month or so to get a couple more paychecks under your belt etc....

If you want to maximize gaming performance, you'll want 2 hdd's in Raid 0.
You can get the cheapest/slowest single drive AW offers, and again buy 2 much faster hdd's aftermarket and save money there too.

Lastly, much in the same vein, you can skimp on other parts on your initial order and buy them through AW later to keep your initial order cost down like say if you want Blu-ray, get the cheap dvd drive and buy the Blu-ray drive later.

In the end though, especially b/c all they offer is the 19x12 screen, you really dont want to skimp on the vid cards or the processor.

That said, this recomended config comes in at 3500$ w/ only 1 year warranty and no other frills and you can expect to spend another 500$ total on 4gigs of ram and 1 or 2 high performance hdd's.

you can get the lowest ram from alienware and purchase the 4 gigs from like newegg and save you a ton of money alienware make good money by charging alot for there ram...

it doesnt void your warranty on your laptop just ur RAM warranty... but I keep my old ram that came with it just incase something goes wrong... but I have heard if you call alienware while installing the ram they will walk you through it and I think honor your new Ram... Ram is not a major issue with a computer compared to a GPU or CPU change...

Upgradeing ram is easier than desktops, although sometimes more tempremental than desktop ram about being seated just right.

But as was said, keep the 1 gig stick u ordered with, and if anything ever requires u to send it back to AW just pop in the original stick (3 minutes of work) and they will never know the difference as they dont put any warranty seals or the like to check if ram had been changed.