Quiet muffler choice & install

[funcrew]

My 325i came with a single 2.5 inch stainless exhaust. The itty bitty Remus muffler is way too loud. I was thinking of this one:

"The Hi-Flow Quiet muffler provides an almost OEM quiet driving experience."

http://www.ironpigoffroad.com/mechanical/exhaust.shtml

Also, can a good connection be made with clamps and muffler cement, or is it mandatory to have the new muffler welded on by a shop?
http://www.jegs.com/i/Dynomax/289/35958/10002/-1?CT=999

Thanks!