Here is a quick write up on how to do it your self along with the pics
First you need to jack the rear of the xB and support it in jack stands. Then you will need a 14mm socket and rachet. You will want a long extension also. First take the front two 14mm bolts out of the B pipe upfront. Let it kind hang there. Then take the 2 14mm bolts out of the rear of the B pipe. The hanger will still be holding the B pipe in there. Then pull the b pipe off the rubber hanger. You will need the rubber hanger peice for the strup B pipe as well. I took the old B pipe out and put the hanger off it and put it on the new Strup B pipe. Then put the new B pipe in there. Make sure you slide the back of the B pipe over the axle and then slide the hanger back on. I put the 2 14mm front bolts back in barely. Just mainly there to hold the pipe in its spot.
Then go back and slide the actual muffler section off the hanger as well. The exhaust should be out of there now. Take the rubber hanger off the stock muffler and put it on the Strup peice. Now take the Strup muffler section and hang it under the xB by the rubber hanger. Both peices should be in there now. They will be loose but that is ok.
Take the gasket that is supplied and one of the bolts and line it up and put one of the 3 bolts in the rear peice. Make sure that you are not smashing or bending the gasket in any way. Now take the remainder of the 2 bolts and get it all put together. Make sure that you tighten all 3 bolts in place. This is where the extension comes handy. Now go back up where you left the 2 bolts in the front of the B pipe loose and tighten them up. Make sure everything is tight and not hitting anywhere. I just grabbed the exhaust and shook it and it didnt hit anywhere. Now you should be able to start the xB and check for leaks.
This took me about a hour total and that was with getting everything jacked up and set to do the work. I hope this helps out.