MasterShakeXJ

so my jeeps been drivin kinda crappy lately. i first started getting some vibes and my first thought was my front ds, so i took it out. and didn't really notice much of a difference. then thought it might be alignment, so i had it aligned and that didn't help much. then today had my local mechanic drive it around and he said its my exhaust leaking. and maybe the cat going bad, and he said "other than the exhaust leak its smooth, even gettin it up to 60." this kind of makes sense to me and kind of doesn't, the exhaust might be producing the sound, but could it really get bad enough to feel like a driveline vibe? it def. feels like it's coming from he front end though, i mean i wanna trust his diagnosis b/c my family has been dealing with him for about 14 yrs. i serviced the diff's like 3 months ago. i guess i should also add that it's been idling rough. i guess it could be hubs/balljoints/wheel bearings etc but i'm really not sure.
and i gotta drive back to school tomorrow, could be a long ride.