If i just put a few bolt ons in my car (header, intake, exhaust) and some rims on my car will i ever have cop trouble?  

haha most likely with an aftermarket exaust.... yes. in more states its illegal to have aftermarket exaust systems, i dunno about the headers and intakes though. but the worse thing you can get is a fix it ticket so who cares.  

how wud i be able to find out if it was illegal?  

internet :P what state you live in? im in cali and i know for a fact that aftermarket exaust is illegal here. i work at the local pd so i need to check out the other bolt on things myself.  

im in ohio, and there isnt much tuning going on near me so idk if the cops are all that aware  

in you live in the country they really dont care. i live in a big truck town with alot of muscle cars and trucks with no exaughst.  

same here godfather over here i dont think there a problem cause i live in Al. in a small town but i see some weak litto ricers rolling around lol  

i dunno, you could always go up to a cop and ask him mpoky haha im on good terms with my local cops so i can do that. and here i see people getting fix its all the time. but i just found a vehicle code book and looked it up. thats your best bet. old fashion reading ftw