Okay...here goes:
1.
Rear mounting bolt: I welded on a bolt to the original grab bar to use as a mounting "stud" (see pic). Those with aluminum grab bars COULD drill a hole and just put bolt through the hole tightening with nuts....unless you're lucky enough to have a TIG welder just "laying around".
2.
"Mid-Pipe" mod: I cut the forward/middle portion of my old junk silencer and used it. The only mod I had to do with it was cut a SLIGHT "pie" shape out of it to sharpen the angle that the pipe met the new muffler. EASY weld/mod with a wire-feed welder and SawZall (or cut-off wheel?). This MAY NOT have to be done with different brands of mufflers OR even stock muffler/pipe. But I can't say for sure.
3.
Rear Master Cylinder Resovoir Mount: Bend it's mounting bracket slightly rear/inward for resovoir and hose clearance (see pic).
NOTES: STOCK head pipe is NOT modified. The 450R muffler comes with an awesome GRAPHITE seal inside the area where the clamp is AND the clamp is fantastic. Try and save everything you can! You won't regret it!
All I can say is take your time and make 'er fit and seal TIGHT.
This isn't brain surgery!
It took me 2 hours to do the WHOLE job: start, finish, clean-up.
And I DO NOT have a shop; just me and my creative mind in my garage.
Keep telling yourself......A Stainless
HONDA replacement muffler for CHEAP (got mine for $31.49 TOTAL) and two hours of my time? Oh yeah! Worth every minute.
By the way....this muffler MAY fit other models....for the quality of construction and the availability of them used, it's WELL worth the effort.
We may as well cash in on those silly 450R folks "throwing them away"!
Thanks for all the interest, folks.
Hope this helps keep many more trikes on the trail!