Considering a Z70Va

I plan on ordering the following from ISTNC tomorrow:

Z70Va-
CPU: P-M 760 2.0ghz $310
RAM: None
HD: None
Optical: DVDRW $129
Secondary Battery for Bay: $89
Intel 2915 Wireless: $40
2 year warr. $80

I will be buying the RAM from newegg.com since it's cheaper. For $120 I can get the OCZ 1GB stick of DDR2 SODIMM. The hard disk I also plan to grab from the 'egg.

I guess that brings me to my first question. My choice of drives. I'm down to a Seagate 100MB/8MB/5400RPM drive and a Toshiba 100MB/16MB/5400RPM drive.

Seagate:
5-year warranty
It's a seagate retail

Toshiba:
Saves $20
16MB cache

Would the 16MB cache make much of a difference? Toshiba's good for 3 years, which I'm fine with. I just don't know about toshiba's reputation.

Second, for the RAM, I was going to spend $20 more for the OCZ since I get a $15 rebate anyway. The $100 sticks are timed 4-4-4-12, and the $120 OCZ is 4-4-4-8. Should I just say f it and get the $100 instead and save myself the time/money?

Third, the secondary battery. I never see anyone mention it. I take out the optical drive and put the second battery in and I get a couple more hours, correct? Is it seamless, or does it require a reboot? What's the catch, besides having no opt. drive?

Fourth, what about the DVDRW? I would like to know which drive I'm buying here, since I'm picky about burn quality to the point where I know the pros and cons of pioneer, NEC, plextor, etc. No 3rd party drives? If I'm getting a good deal on a decent drive, then I don't mind buying it from ISTNC. If I'm getting ripped $40 and getting some crap brand then I want to know where else can I pick up a drive for this laptop.

I want to budget myself at around $1800. Right now I'm below that after the RAM rebate.

Ideas? Questions? Comments? Can I save any more money?

Thanks,
Kale

Thanks for the help.

So just this last thing, then. What kind of DVDRW drive comes with it? Is it NEC, etc?