If a big ugly high mount single is the way you want to go, then you best be keeping all the stock bits in the shed.
If you get pulled over and stickered, you'll be off to Regency VIS, basically anything other than a stock car wont pass (there have been some lucky exceptions to that), in which case, you take a weekend, and put all the standard gear back in.
It is possible to get everything engineered, but it's hideously expensive, and on the side of the road with a pissed off traffic cop, it's not worth the paper it's written on.