Nothing wrong with the pacesetters if you put them in right the first time. To weld in the v-band its best if you took the y pipe off and rest of the downpipe so that the flanges can be welded on each. If you take the y-pipe off, you might as well take the crossover off with it and weld that to the y-pipe, so before you take the y-pipe off mark where it is lined up at on the y-pipe. So that way all you have to do is drop the y-pipe through, hook it into the rear header, clamp it and tighten the v-band. Or take the rear header out and weld that also.
I've had the exhaust tack welded to the y-pipe twice now.