where is the best place to buy one? I don't really have the time to send for one online so i'd rather just drive and pick it up on the spot.

 

by the way its for doing my single to dual conversion

 

There are only two catted H pipes. One is on your car now and the other is from mrt. The MRT pipe could be far depending on where you live and it's very expensive. Personally because I've looked into it too, I would buy a pypes H from Brenspeed and then have an exhaust shop weld some high flow cats in. You can probably get higher flowing cats by not getting them from MRT. Pypes has mini ones and Bassani are the best but are not sold seperatly. The only thing holding me back is pypes quality which isnt the best.

 

Generally you cut your Y pipe and install the H. Your stock cats stay on the car. (the H attachesto the cut Y right after the cats)