can i buy parts for like an is300 for my 95 gs300.. like headers cam gears and what not???

 

NOPE, I do believe the heads are slightly different

 

how about parts from 93-97 supra??

 

Yes, those will work as long as they're not for the GTE motor Headers might bolt up to the head, however, may not bolt up to your exhaust

 

you can get hks cam gears but for 93-up supra (non-turbo).

 

I have titan cam gears on my car

I am going to find out of an is300 header will work hehe (getting one for real cheap and thought I would play around)
and if that does not I am going to use a xerd supra header prolly and then do a full dual exhaust