IMO anything bigger than a 20G and a FMIC is necessary.. Yeah you could get away with a TMIC and a 30R, but you'll be leaving alot of HP on the table, as well as safety.. The 30R createes alot more heat, and will heatsoak the TMIC in no time..
As for the kits, all of them wil make basically the same power, even the perrin kit with the older style exhaust housing.. It comes down to what you prefer.. I wanted the wastegate to be rerouted back into the DP, and at the time the perrin kit was the only one that did that, plus it was alot cheaper so i went with the perrin kit.. The fitment could be alot better, but i didnt do the install so that didnt really matter to me. If i had to do it over again, with prices being as close as they are now between the kits, i'd have to go with the either the UR kit or the full race kit if i had extra cash.. UR is the most proven kit, and if noise is an issue like it was with me you can havbe the wastegate rerouted back into the DP for an added cost..
Perrin kit is good and definately works, but the horrible intake that comes with the kit, as well as the poor fitment, IMO they could have done a much better job and now that they have raised the price i dont think that kit is worth the cash, especially with the horrible intake..