The factory dual set up is exactly like the stock set up except it has the second outlet. The driver side muffler has a restricter on it which creates enough back pressure to divert some exhaust to the passenger side. This set up does not add alot of noise.

As far as the outlet goes, Volvo made one bumper. They cut a hole for the AWD exit on the passenger side and "plugged" the hole that was molded in and used for front wheel drive cars. I guess it was cheaper that than molding two separate bumpers for FWD or AWD.

This system clamps on, clamp is right over the rear axle. No welding needed. Volvo simply refers to it as a "muffler assembly" for 2000 V70R. This is one piece with both mufflers, cross over. All you need is two tail pipes and the bezel for the exhaust. This is an easy swap. be sure to buy the PAIR of tail pipes since Volvo's new part is 1/2 longer than the old ones.

Good Luck, I used to have the part numbers....I will see if I can find them for you.