[lonewolf]

If you do some reasearch you'll find magnaflow make a LOT of mufflers. At first I thought there was only a couple 2in 2out but found out they make about 20 of them.
the one you used on the Z is a small can so not much muffling ability.

One thing you must concider is inlet and outlet size and length because that effects performance.
It can get complicated if you don't know what your doing.