Sam q off here sells allot of good bits which makes the 20v much easier to do than it used to be... You can use stock ecu with a dizzy relocation kit which puts it at the front of the engine which is still under R&D (hurry up sam) and his water kit looks good too. Wiring isn't that scary either, sure it is a little harder than a 16v, but not stupidly hard. Main reason most ppl go after market ecu is they ditch the dizzy setup due to the clearance issues, whatever you do don't bash your firewall to make it fit. It looks ugly and i'm unsure of the engineering side.

From my experience with the 20v and i've owned a quite a few of them (mostly fwd tho). The blacktop is a much nicer / free reving engine. To me the difference in the 20v's is similar from getting in a bigport vs smallport between the two. You'll spend 2-3k on enhancing a 16v to get it to perform about the same as a healthy blacktop. Silvertops have more torque , but if you keep the revs up to a blacktop it doesn't struggle.

Budget wise are you doing most of the work yourself or are you relying on someone else?