I will probably get it tommarow

if the loan goes througth ok, but just wanted to know if people thougth this was a good deal. I can get a 1998 gp gt, fully loaded, leather seats and moonroof, with 50,022 miles on it for $6750, the only hitch is that it is a coupe, but I think its still worth it, I tested the car and it has plenty of power. As for upgrades, keeping in mind I still gotta pay for the car, what are some good simple DIY upgrades to try to get this maybe around 210-220hp? Also, has anyone tried these:
http://www.lecryo.com/purepower.html are they better than iridium, and how about engine durability with these, also there was a site that I'm looking for that shows upgrade for gp. The site showed about the extra power drop in the fuse box, heated seat install, and other 3800 upgrade. Please let me know if you know this site.
Thanks