H- or X-pipe on side exhaust

Loco is right on the muffler placement mention. Actually, the bolt to the header collector is not a great idea if room is available to move them back on. You would be much better off running exhaust pipe into a "X", then into the mufflers with some pipe after the muffler.

Have the pipe bent or use comerically available bends cut and placed as needed. This you can do yourself, it just takes some time to do. Use a chop saw and weld it up.
AAR mufflers are available FYI.
Regular mufflers can be used as well, it's just the pipe after the muffler will be a 90* at a min, or a cut up "J" bend and an additional 45* after it to exit the pipe where you want it.