my mom has a n/a volvo 940 wagon, somewhere around 110k, stock exhaust system, not sure about the cat...recently it started to get really loud....like the ricey hondas and acuras with their fart cannons...and she says sometimes she sees black smoke when she first gets goin....i dont think shes running rich...everything is completely stock....it sounds like carbon deposits from the muffler being old? i really have no idea..she wants me to replace the exhaust system..but can anyone tell me if thats what it sounds like? just the muffler..etc....i was reading up on volvos..they have like 5 diff mufflers and/resonators??? can someone clear me up on this? im not use to euro cars..i only tune japanese cars... (no not like the fast and the furious crap...just very fast with a stock appearance..) i found a replacement rear muffler for 95..or i think its the rear....if i replace that...will her problems be solved? thanks in advance