why not weld a set of flanges in the crossover pipe so you can "split" the exhaust to get the trans out.or flange the system behind the mufflers so you can drop the front portion as one piece.crossover pipes do help power output imo.ive seen this first hand on my car.ive built several exhausts on my 340 being a fabricator by trade.the one that made the least torque on my car was a true dual(no crossover) mandrel 2.5 system.the system that made the most power across the board was a 3" x pipe with ultraflow mufflers.off idle and midrange torque are excellent.honestly the results are not what i expected.im not sure there is any magic formula to determine how every exhaust system will react to a give combo.