I'm expecting having to have to grind down a few things, and as far as comfort goes
Have you ever been in a 240Z or AE86 Corolla hatchback? There is no such thing.
The idea isn't to take it down to the bare minimum for the meantime, but remove the simple things. Weight reduction is the best thing you can do to any car, since all the attributes gain from it. Eventually getting a real drivetrain and a decently built motor will have to come into play, of course. I used to own a '93 3000gt vr-4, which weighs in at a whopping 3950lbs, without driver. I eventually got mine down to the 3500lb range, and everything was better than anyone else who was making the same power (almost 450whp) as me. Turning and braking benifited the most. With that kind of weight reduction, it still weighed more than a stock SVX, so coming from there, you can see the appeal.