I'm thinking about what I'll be doing to mine when I put the 292 in it.
If you have two collectors, definitely use an X or crossover pipe. I believe that will improve both sound and performance.
I plan to use 2 1/2 inch pipe for the whole system.
There is a muffler, I think its a Flowmaster, that has an internal X crossover. I'd like to use that with another muffler on each rear pipe. (I like quiet power.)
To keep it simple I plan to have the outlets, with slight downturn, just in front of the rear wheels.