208 vs 308

I posted this in the general chat also:
Hello to everyone on this forum. I'm new here and haven't owned a Ferrari for about 15 years. I've had most other exotics over the years. I am starting a project and i'd like some advice. I am going to acquire a Bertone bodied 308 that will undergo some performance enhancements. Specifically, supercharging, suspension, brakes, wheels and tires. The one absolutely essential part of this project is euro bumpers. I know most people don't love the looks of the car but to me its one of Ghandini's best but the euro bumbers are essential. (To show you where my head is I put up with a euro bumpered Khamsin as my daily driver in Manhattan for many years purely for aesthetics.) Therefore I can either source a 308 GT4 in europe, ship it here and do all the work; get all the parts for a bumper conversion and buy a U.S. car; or buy a 208 that is for sale here in th U.S.
I should mention that federalization won't be a problem as I plan on shipping the car (back?) to Europe when it is done for use there.
Option one is a ludicrousely expensive way to obtain a base car because the exchange rate puts perfect European gt4's at about $40,000 US before shipping. Option two is possible but will require sourcing and installation. I read of someone spending about $10,000 for just this. Option three would mean installing a 3 liter engine BUT since a supercharged engine fairs best with solid exhaust valves, perfect top and bottom ends, new chains, etc. i might want to do that. As an aside I was thinking I might get some takers for the two liter engine on the websites devoted to Stratos replicars. It would certainly look the part and be closer to original spec than the 3 liter some people install.
So here come the questions:
Exclusive of what i'm going to change anyway, what are the factory specification differences between the cars? I know the 208 has a black metal dash (which I prefer) and the badging of course. But it seems to me both could be purchased with a multitude of trim options, A.C. etc. Are there any drivetrain differences like smaller half-shafts, etc. to reduce weight or due to less HP and torque? Anything that would stop me dropping a 3 liter block right in? Anything else I should know? You time is appreciated. Thanks.