dont do a top swap without help if you dont know what youre doing. dont do the SS kit before you think about doing a top swap. its cheaper and probably better.
turbo: all out fast car; expensive
m90: can be made fast as hell, but usually just moderately fast; depends where you get your parts
n/a: can get them to usually run low 14s, high 13s with the right amount of parts; cheapest route