I own the Systemax Pursuit 4200.
Basically mine was perfect till on a certain day I was viewing the LCD at a very irregular angle. I noticed that I had these hairline vertical lines running from left to right of my display. At the optimal viewing angle I could not see them. In the end I decided given that they were consistent and I could not see them at the optimal viewing angle I would just keep it cause I loved the lappy quite a bit.
As for your problems
I would have def returned it regarding the LCD issue, however if I returned my notebook based on its ability to overclock at ANY store in Australia they would have told me to dislodge my head from my ass. Seriously this is not a reason to be displeased with your notebook and in no way does it mean your card is defective. The nature of manufacturing lines is such that there is a large variance in the quality of ram and GPU that is produced. HOWEVER this does not mean your card is defective, it just means it is going to run at its required speed and no more. Furthermore given how compact mobile devices are there is not alot of space to implement an effective heating solution. Nobody should really be pushing their lappy beyond what it was 'designed' to do.
If you want advice, only seek replacements for things that your notebook was meant to do, yet does not. Overclocking is def not one of these things
Just putting in a word for those hospitable people you are dealing with who sound like a fabulous bunch. However sometimes you can take a good thing and run too far with it :P
Cheers & Good Luck