Piecing together a hci 5.3 and a 100 shot. Curently running 1.75" lt's ory to a single 3" dumped borla xr1. Im anxiously awaiting the sp engineering dual 3", but do I need it? Ive seen some nasty ls1's on a single 3 that flows well. I could easily step up to a 3.5", some have recommended a single 4. But the y merge seems pointless to step up to 4". I also dont want to dump this much $$$ and bottle neck it. Thoughts?

 

I would keep it single 3".

 

Cant beat the sound of 4inch or dual 3 inch

 

^ I'll second that

 

Single 4". My buddy's VMax picked up a lot over dual 2.75". Cut the Y at the widest part and weld a 3.5" to 4" adapter on then run your 4" exhaust. If you have a torsion bar setup you'll have to clearance the pipe a little. Should be fine on a 2wd. The 4" sounds way better too. Much deeper note