When I bought my silvertop from SSS Automotive they recommended an autoelectrician that specialises in wiring up jap imported engine. I think they said he charges $500 for a 20v. I wired mine up myself but although its not that hard, if you're not used to doing that type of work it would be money well spent.
There is a fair amount of info available off the web but it took me a fair while to do it as I wanted to be really sure everything was going together right. I ended up unwrapping both my old 16v and 20v looms to figure out where everything went before chopping wires etc.