exhaust issue

for one i was wondering if the exhaust heat shield is even needed or can i jsut take it off. and 2 i was wondering if 421 exhaust headers are better then stock 91 civic dx hatch back headers

Heat shield is there to keep the heat from spreading farther into the engine bay. If you remove it you more than likely wont see a differnce. Yes you will see some power out of a 421 header. Honestly I would save up and do an engine swap. I know you dont have much income sence your 16 but with a summer job you could probably save enough to get an integra motor from a junk yard for a few hundred bucks (localy around 500 for motor and tranny, but I dont know where your located at). If you do put on a header make sure you put a good exhaust system on because it would be kinda pointless to put a good flowing header on a shitty flowing exhaust.

beleive me if i could have a integra motor i would but right now my motor is under waranty or so ive been told and well i dont have the tools to swap a motor out

that header will more than likely void that waranty