The 99-04 GTs have better flowing heads than the previous years' Cobras. The 97-98 have lower power at lower RPMs. So if you do get an older model Cobra you will want to upgrade the heads.
If you aren't planning on doing this for another few years why not save the cash until you are ready to buy? I mean who knows what could be out by then. Hell, the current year GTs have 300bhp. Who's to say that in 5 years they will be up to 400bhp. I heard where the new V6 Camaro was going to have 300bhp with the V8 over 400. And the Challenger will be around the same numbers. Ford will put a Mustang out on the market with higher numbers to compete. It may not be as high but it will be higher.
If you aren't planning on doing this for another few years why not save the cash until you are ready to buy? I mean who knows what could be out by then. Hell, the current year GTs have 300bhp. Who's to say that in 5 years they will be up to 400bhp. I heard where the new V6 Camaro was going to have 300bhp with the V8 over 400. And the Challenger will be around the same numbers. Ford will put a Mustang out on the market with higher numbers to compete. It may not be as high but it will be higher.