Dunno bout the shocks but +50mm is roadworthy legal, if you have a look thru the forum you'll probably find a revue or three haha.
Price sounds about right for the steering wheel grip .
After you do the shocks give the tank a good degrease and was then go for a drive and see if it leaks, if it doesn't then job done!
Aftermarket would be half the price surely, did you try bursons or repco for the seatbelt??
Hit matfew up for the hinge he'll help you out