I got 3 inch straight pipe into 4 then 5 inch footlong tip, now my question is will it sound better or worse with 5inch all the way with duel outlets behind rear tires or 4 inch exhaust with the same 5 inch duel outlet tips behind tires? Truck shop here has a couple wrecked schoolbuses ones got 4 -ones got 5 inch i can get one or other for free. good pipe too!!

 

Generally the larger the pipe the deeper the tone and less spit sound.