Nicks: should I?

if your never going to sell it why worry about what others think? if there is a slight chance you may sell it, why would you have concern? is it a loss of 'potential' money. harm of the originality?

nicks displacement increase should not have an effect on outward apperances of the motor. it's mainly internal. the loss of the CIS would be the most noticable.

personally do what you want. to own the car and worry about the next owner or potential profit takes the joy right out of the car. it's a car and only a car, make yourself happy with it, not the next guy.

 

unless you turbo it the money cost for HP upgrades are better spent getting a more powerful Ferrari.A 308 is never going to be a screamer unless on boost then you need to upgrade the suspension and brakes

I went through the same delima with my 328 after about a year, bought a larger throttle body and planned on doing other mods to it, then thought about it and ended up buying my BB instead which weighs 50lbs less than the 328 stock and has 100 more HP problem solved, all the GTS Ferraris also have too much cowl flex to really be a ultra perfomer anyway the reason the super performing Ferraris are berlinettas.

 

You could buy a used motor and build it for power while keeping the original as is. Here's a start http://www.ferraripartsexchange.com/308QV_wreck.htm