Isn't the SM4 the same as vipec? That does do sequential injection. You are right though, you need the mapper / installer to know what they are doing and what they want to acheive to spec the right one, clearly a megasquirt would not compare.

TurboTrev look away as I am talking about my car and personal experiences and opinions and I know you hate that...DO NOT READ ON.

The main "upgrades" I wanted were 1) everything new as I was fed up with chasing misfires and the car ran differently each time I drove it, I know someone like MSD could have probably sorted this but they were SOOOO far away from me that the cost of getting the car there and back was a big proportion of the replacement cost (plus cost of things like loom etc)

2) I no longer wanted a car running on a distributor...things have moved on with coil on plug...I had an MG metro with a distributor and I was glad to see the back of that!

I wanted to end up with cam shaft trigger and delete the dizzy altogether

3) I wanted it live mapped, I was recommended to Mark Shead as a guru and someone quite local to me who could rolling road close to my house AND live map it and he no longer maps the old stuff.

4) My car had been chipped and mapped before and was far from perfect so did not want to throw good money after bad, I wanted to fix and forget.

The Vipec also talks directly to my Toucan dash with tell tales