I am looking at putting dual exhaust on my 89 SSE, can a set from a newer SSEi or Monte C be put on without much problems? I plan on cutting out the back ground effects to incorporate the tips.

Well, the big secret comes out. Our dual exhaust is fake. It splits after the muffler. You don't want to go true dual on a NA Bonneville unless you heavily modify the sucker. You'll steal too much backpressure and kill your Torque. The same thing can happen if you go 3" exhaust.

If you want the dual tip look we have on the SSEi and SSE, that'* pretty easy. Some guys suggest using the muffler off of an F-body. It'* already a dual-outlet. You'll need some custom bending to get the tips to opposite sides, unless you want them to come out together. Go with a higher flow Cat, and remove your resonator.....not sure, but I don't think you have one. Now you've got a pretty free-flowing exhaust, and a bit better sound, too. Take full advantage of this and do the intake at the same time. Gotta let more in if you wanna poop it out the back.

Shhhh don't let the catback out of the bag i know its not truly dual
I just wanna do from the pipe to the muffler, a dual outlet one and tailpipes either side.
Midas quoted me a small fortune

Do you weld? If you do, or know someone with a good wire-feed, I'd go to a salvage yard and get a camaro or firebird muffler. You'll need custom outlets to get to each side, and weld on a new support on each end, or a muffler shop could do it for you. You'd save some money bringing your own muffler in. Curious.....what did Midas Quote you? There'* a few modified exhausts here already, and I'd be curious to see what they think about your quote. Exhausts typically don't get really expensive until you go all the way back to the downpipe back. Yours shouldn't be bad, especially if you're leaving the Cat.