The civic si hatchback is more upgradable but, i think the civic hatchback is more economical. I had a 94 hatchback and it was the best car i ever had. It is really easy to find parts for them because all of the motor parts are interchangeable with any 92-95 civic. The hatchback is a really light car too (i guess the the si is to) but i have seen a lot of really cool stuff done to the hatchback and i have seen a lot of fast hatchbacks too. My hatchback now runs a 13.0 in a quarter mile. I would definitely suggest a 92-95 hatchback.