I have heard they changed the exhaust but did Suzuki change anything else? I am picking up a 2001 XL7 and if all I need to do to get the 15HP is exhausty I may be tempted!

I THINK...in 2001 they had the same 2.5L as the GV's.  2002 and up they were all 2.7L's (well, except for the lucky bastards with the diesels overseas).

There was a hp boost in about the '03-04 time frame and that was pretty much just exhaust.  Mandrel bends and better routing basically.

Haven't done it on the XL7 yet but on our GV simply replacing the stock garbage can of a muffler with a 2" in/out Magnaflow netted a nice little seat of the pants power increase.  Nice sound too.  Some of the gain was also probably the 20lb weight saving by ditching the factory muffler...big SOB.

all xl-7's have the 2.7l up to 2006(in the US).  As for the HP it's just cat back system for the 15hp's

George