ok this is the problem my brother blew up an rx7 13B engine it had 146,000 miles on the last 7,000 miles pretty much from 139,000 to 146,000 he had a single straight thru exhuast. after he blew it up he gave it to me (aka Little brother By the way im 15 and a major gear head) so i just bought a used 13b engine wid 67,000 miles on it. My question is can i use the straight single exhaust wid glass pack or should i use the stock dual exhaust which one will be better for the engine

 

The glass pack exhausts wont last very long. Rotary exhaust pulses are pretty strong.

 

You'll destroy the glass packs in a week, especially if you drive hard. Put thte stocker back on till you can afford a good exhaust (Racing Beat, HKS, Apex'i).