I figure I can but would it look funny with just one cutout? Or should I - could I swap the SSE or SSEI rear bumper?

You can swap bumpers, but in order to make it flow with the rest of the car you'd have to swap the side moldings and front bumper as well.

You could make another cutout on the other side of the bumper...with some work it wouldn't look too bad.

DUAL, not duel.

And it'* not really dual. It'* a double outlet, not true dual. I think I prefer double TIPS on the right side of an SE, just visible below the rear bumper skirt.

Yes, you can go to a dual outlet muffler on your 99 SE. That is exactly what I, and many others, have done with our SE models. http://www.bonnevilleclub.com/forum/...ic.php?t=40304

But I disagree that you could make cutouts in your bumper and bumper cover to accommodate the tips, and still have it look good. I think the only reasonable way to do it, -and it'* what I did, -is just sling the tips under your existing bumper, and keep the rest of your car the same.

Otherwise, you will need a lot of mouldings to match up the sides with the bumper trim if you swap the bumper from a dual-outlet model.

You can play a bit with how far apart you want the tips to be, I requested my exhaust guy place them in the same location a dual-outlet Bonnie has them, and provided pictures.