i have a set of pacesetters on my 4.0 the y pipe i had to cut in the middle due to it not being wide enough then clamp some flex pipe over the cut section, other than that i was having a leaking prob on the drivers side rear tube so i got new gaskets from pacesetter and found that the prob was the weld around that tube that mates with the gasket wasnt wide enough to contact the gasket so i ran a quick beed and ground it flush with the weld and now they are leak free, other than that i think they are great and you cant beat the price as compared to other brands they just take a little work no biggie!