[surfbeast]

Newer is better! Sure the parts are a bit more now but they are getting cheaper. Also, most of the older Cobras are high milage and used/abused. If you want the HP then you have to be willing to pay for it. You can make your 98 GT a monster if you pay the money. Look at Hammers car! Also, do a price comparison. If cost is your main objective then go with the best cost to HP ( cost of car divided by HP ) for you. But also look at the longevity of your car and the total dollars you need to spend to get to your goal.
The 96 - 98 cobra is a much better car just like a 99-02 cobra is better than that and the 03 Cobra kills them all! It all comes down to HOW MUCH MONEY YA GOT!!