Sounds like you made a good choice going 2.5".. Anything larger would likely result in reduction of power due to lost velocity, for anything under 400 horsepower. On my 85 I stared with Borla 2.5" Cat back (3" intake split to 2 -2.5" ), which sounded great, and then added TPIS headers (3" collectors, 1-3/4" intakes) and deleted the CAT and Airpump., which sounded deeper but made it louder. I did the Borla cause I absolutely Loved that sound at Idle. Very bad ***. When I drive by myself, I love it, I can just listen to the pur of the engine, no need to even listen to a radio. BUT.... the side effect was it became impossible to carry on a conversation in the cockpit while driving, just too loud. The novelty of it wore off quickly. I put the CAT back on, and that helped a lot to tame the noise. I majorly redid sound proofing when I changed the carpet, and that barely made a difference. Although I like the sound, for functional reasons, Im considering switching out the Borla mufflers to something that would be less loud at cruising speeds..(no mufflers is less loud). But I want to keep my Borla rear Y-Pipe that exits with 2.5" pipe. I didn't go back to stock cause that's only 2-1/4". So my question to you is..... How do your 2.5" Allens chambered eliminators sound at cruising speed? Conversation compatable? Anyone have any other recommendations for lower volume mufflers that support 2.5" pipe intake? (understand might need to make the connecting pipes).