OK, already tried the Search button. I know a 5x8 oval muffler will fit, but has anyone tried fitting a 5x11 oval muffler? I plan on getting a MagnaFlow(#12586) 2.5" i.d. center/offset, 22" case length/28" overall length muffler. I'm trying to get the longest, biggest, and quietest straight thru muffler to fit under my B14. Just want to know if anyone's tried this before I go under my car for measuring. TIA...sr20jet said:I measured my stock exhaust and it's 13"x10"(L x W) casing, hope that helps.