Really depends on what you want and what your skill level is for making a tube chassis and designing all the suspension etc.

I have both and the Fiero frame certainly has its many drawbacks but a lot of the electrical etc. is already there and a lot easier to fit so easier in the end run in my opinion.  That is, if you don't mess with the unibody too much.

Now, I also cut the roof off to make a convertible and I think that was a terrible mistake on my part.  It has taken a lot of time and effort to get the frame sorted out to be safe and rigid again.  You also work around the original frame and chassis in quite a few areas to make everything work once you start modding an original.  Working on a unibody gets pretty involved once you start moving things around and cutting it up.

With a tube frame, you really need to have a good understanding of the dynamics of suspenion etc. to make a good car.  I bought my frame from a fellow that designed the frame around a Fiero cockpit but he had many years of race car design behind him to properly set all the various moving parts up.

Again, your skill level, patience and what you really want as an end product is what will drive you in your ultimate decision.

Good luck
Don

if you want the easiest, go with existing car, i used a few existing cars for  my projects

I agree, it all comes down to what you want in the end and what your willing to pay for it.  IF I dont have to sell mine to install the new hvac in my new house(long story short, was supposed to be included, turns out it wasnt, now Im looking at a $13,000 bill!) then mine will be a boxster cockpit with tubular rear and possibly tubular front.  EIther way, Im not sticking with the wimpy 6 banger porsche engine nor do I want cheesy looking replica interior OR a fake engine cover.  It all comes down to what YOU want in the end.  For instance, Im not even gonna run lambo badges

Ok, I got the idea, two different perspectives

I love the extreme cars, and the DNA cars, and they are really beautiful and practical , because they use a nice "everyday" car that can be customized with aftermarket performance extras, these cars are not chopped and stretched like a fiero, and they keep mostly the same essence of the original donor car. Avoiding structural problems of chopping the roof and reinforce the stretched area, electrical wiring and everything.
For me, a everyday car will be the best solution for my project, but also building a tube chassis, and adding a powerful engine also is very attractive way to go.

Talking about my project, Initially my plan was to make a custom tube chassis for my scudero body,  then set a Cadillac engine on the back part of the car, and then build everything from there. I know I can do it, because I´m not in a rush to build them, but I don´t want to get in trouble with a "fragile" or "delicate" engine as the Cadillac engine. I have some friends who owned cadillacs (96 to 99) and also a good mechanic friends, and all of them agreed that those engines are a pain to install with all the sensors and electronics from the car, because this cars are like pioneers with all electronics controlling the engine, gearbox, and everything, so I really want to avoid that.

I really want to have a engine that could be seen through the rear window, that would be a aesthetic plus for me, also to make a burnout with the rear tires. Here in my country the fieros are imported cars that are considered as trash cars, because they are too old and most of them in regular to dreadful condition, and the MR2 is not available here, so I would have to stick to a front engine car like the peugeout 406 coupe, or something similar, with front engine and front wheel drive.

Is it too bad?

Please give me your oppinion/advice.

Best regards

JELP

How's about using a decent Fiero (if you can find one) put a good strong V6 or V8 in it.  and adapt the fiero to accept the extreme 360 kit? Only thing structural would be to change the wheelbase. That would give the motor in the correct place and the rear wheels spinning away!