Engine swaps are done either as neat ideas, or as last resorts for getting the absolute most out of a chassis. Not as a "necessity" for turning a cheap used car into a "tuner" car. It's just too impractical in most cases (especially putting a long straight-six designed for RWD/AWD into the cars you listed in the first post), and although you may not get the same amount of horsepower, tuning what you already have is almost always a cheaper and more sensible option.
I understand you're young and excited about the idea of having a cool car, but really, unless you have a lot of money and a lot of mechanical know-how, just driving what you end up with and enjoying it for what it is will be more than enough. I guarantee it.
We car enthusiasts are who we are because we enjoy driving, not because we all build our cars up to make them enjoyable to drive. Think about that.
Rep to you Wolfe for that. Perfectly stated I feel.
Engines swaps are only really an option if you absolutely love the chassis for some reason, or if its an easy, direct swap. Having done an engine swap, and helped on a couple of others and such, they are a huge amount of work. Even for engines that bolt directly up, due to wiring and piping. For what I spent on doing my swap, I could have gotten more power from doing a cheap turbo kit on my MR2, its just I want to eventually go further with the car, because I love it. This will entail alot more work, as I'll have to get a stronger transmission, redo the bell housing on it, possibly different drive axles, redoing the shift gates in the car to accommodate a possible 6th gear. And thats just what I know will have to be done to support building the engine, not the actual building it part. It would easier, probably cheaper, and I would get more power just to get a 2nd generation MR2 turbo
The cars you mentioned would be 8 times more work, as almost EVERYTHING would have to be custom made, from suspension parts to drive trains. To due those swaps, expect be an expert metal worker, or spend several grand just getting parts fabricated. Then there is the engine, wiring, labor, and so on. That, and you might just twist the chassis on those cars with a big engine. You might not realize this, but 200 HP is alot for a small car, and 400 HP is just kinda absurd in most things.
If you want to do an engine swap, stick with something has is commonly done for your first project. Such as basic engine swaps for Civics, Lancers, Sentras, Corollas and such. It will make your life easier for a first car, and you'll find fixing stuff you break (and you will break stuff) cheaper.
That said, Wolfe had another excellent point about enjoying a car. A fast car does not mean a fun car, and a fun car does not have to be fast. One of my favorite cars to drive was a 94 Tercel, because it was cheap and light. Sure, it had a whole 84 HP (new, probably 70 when I got it), had a 4speed manual and was a total econo box. But it was fun because I could go drive on dirt and snow and not worry about it, parts where cheap. My MR2 is fun, but driving feels like a chore at times because it just can't go on dirt or snow with the suspension. So keep that in mind to when you look at cars.
EDIT: mnm_bmx... VW beetle drifting.
