I've tried megasquirt and it won't work as you need sequential firing on 5 cylinders and you need 5 coils. Megasquirt should work ok on the other engines just not the 5 cylinder unless you can write your own asm language and completely change the megasquirt code. Also it can't control engine ignition so you can't run any advance and it may not be able to control the VVT which is pointless I my opinion. A decent standalone that would be better than the DASTEK piggy back will cost over £1500 plus you gotta wire it in, buy compatible sensors and then get it mapped which I can't see given any more power for the money spent. The standard Fiat ECU is very adaptable I feel it's a waste of time and money to go standalone on a 20V N/A unless u've don't something out of this world which needs better control. I would say use unichip and be happy with that.