I had flowmasters on my truck and then i just had a y pipe installed and was thinkin about getting 4 inch tips. What will this do to the sound. Also i have them coming straight out the back would i have to get them going in the 45 degree angle with each on behind the tire ?

 

I went from 3.5'' and straight out the back to 45's with the 4" tips with my si/do 40 series 2 chamber, I loved the sound change, I could hear it alot better in the cab, and it looked alot better IMO. The 4" tips made mine sound deeper and it was louder.

 

4" Magnaflow Tips.

 

 

That red back end says pretty much "in your face"
I LIKE it!

 

Thats what 4 inch tip with no muffler, out in front of the rear right tire sounds like.