1) Yes most of the same rules apply to the imports as do the domestics. more fuel+more air= more HP
2) and 3) For the money the prelude H22 swap is probably going to be your best bet. There is little wiring that needs to be done and it is almost a direxct bolt in to the '90-'93 accord (from what I know). This will give you around 200hp to start with and around 160tq
4) I've always lived by the rule that unless you upgrade the fuel system or like rebuilding your motor you should only runa shot of nitrous that is half of what the stock motor puts out origionally (ie 100shot on a 200hp stock motor, 75shot on 180hp motor..etc)
Good luck with your sleeper