Over 500hp.....3" exhaust...or 2.5"?

[68GMCCustom]

Need opinions on my exhaust system for my truck. Its a roughly 550hp LSx with 1 7/8" headers and 3" collectors/reducers. A buddy gave me some low use 2.5" turbo mufflers and is trying to get me to go 2.5" but my original plans were for a 3" system. There's really no room for an x-pipe (within the frame rails) so I had planned on running an h-pipe over/under the driveshaft yoke, mufflers in front of the CPP trailing arm crossmember with the pipes going thru the 3.5" oval holes in it. Not sure from there....exit out the sides in front of the tires with some ovals notched into the steps, or over the axle and dumped...out of sight.


I know I would probably get better torque out of a 2.5" system...but feel the motor might need the bigger 3" system to reach its potential while still being "muffled".

Thoughts?