Thanks for the responses, appreciate it.

The use of three maps is primarily so i can play if im honest. The car is my toy, my project. I'd like first map as easy driving, low boost, smooth response, then map 2 to liven things up a bit. Max safe boost, over fuel a little on overrun for pops and noises etc. That kind of thing. All in the name of fun and smiles.

Map 3 i'll use to play with myself, so to speak. Try different things. Learn.

I recall the 1.8 blacktop runs 10.0:1 CR if im not mistaken?

Theoretically speaking, could i use a Bi-metal gasket from Ferriday Engineering in 1.0mm thickness to reduce CR to suitable amount with standard pistons? They quote that a decomp plate is fine to use even with only one headgasket but i'd rather use another route.

I can still find turbo pistons to suit without spending big money on a set. But little machining would be needed to fit Ford conrods.

I plan to have conrods shot peened for peace of mind.