Pricing is relative, I have a Termi exhaust on my Duc 998 super bike, new retail they are $2500 with the ECU, however my local dealer
MotoCorsa in Portland runs sales on NOS sets and you can step into a Stainless Termi set for under $1000.
I have multiple Buells and have several exhausts, All stainless, and paid a fraction of that. One of the best ever made in the Buell exh shootout is the Micron exhaust. Hydro formed pipes and stainless can. Sounds great and dyno proven to give the best performance out there.
backa few years ago they were about $1500 for the complete kit. But i paid $400 for each set i have. I also have a "Free Spirits" polished reverse can Stainless system, a work of art in gleaming stainless. Unbelievable,, I paid $1000 for the complete kit. Its going on my XB12SCG project. theres a guy on the Buell XB forum building very nice hand built and dyno proven Stainless systems for both the XB series and the later Buells run you about $1200 from the cyl head to the tip of the muffler,, be interesting what he could do for a Norton as the Buells are far more complicated.
Here read up what the Buell guys say,,,,http://www.buellxb.com/Buell-XB-Forum/General-Motorcycle-Chat/the-big-buell-exhausts-topic
thats just one of MANY posts on this topic, but $2000? You can get a full titanium system for a Buell.
Keep in mind the Buells run EFI/ECM and tons of guys doing their own tuning, fuel maps and tweaking their systems. All you need is a laptop or a handheld smart phone and you too can tune at will. Someday the Nortons will be there as well.
I have promising leads on some highly recomended guys here locally who can make exhausts for anything out of Stainless and one of them built multiple exhausts systems already for the Norton America bikes and a local multi brand race team.
Personally i would NEVER pay anyone $2000 for an exhaust.