Then buy a Carrera 4 Turbo Look as that is likely to retain its appeal and value.
Tweak a good Porsche with history and you are almost definately digging a hole. That is unless you use a recognised Porsche specialist to do the work, after which you could probably have bought a later model car anyway. And although you say you'll hang onto it now, what happens when 993 and 996 Carrera S prices get to within your budget?
The turbo look involved far more than body panels. Suspension, brakes and wheels/tyres were upgraded. Check out some of the Porsche books for full details.
If its a good car, then enjoy it for what it is. Based on my own short experience, you will not be disappointed.
Migration info. Legacy thread was 19875