Defratos is losing about 2psi at the top end.
Assuming the pressure drop IS because of his FMIC and not a simple boost leak, then that amount is excessive. A drop of 1psi is 'normal' for a FMIC.
BUT... Defratos is running the Stock ECU and hence stock boost. The S3 doesn't need a FMIC at that boost, it simply doesn't generate the charge temps, especially in winter. If his logs are recent then ambient air must be less than 10°C, i'd be suprised if he was hitting more than 35 - 40°C inlet temps with a FMIC - I get 60°C!
So, basically he's introduced a pressure loss that the car doesn't need. He's not even offsetting that against a usefull drop in inlet temps because the car doesn't need them either! It'd be interesting to see what CF's he's getting cos i doubt even without a FMIC that an S3 needs any timing correction, except perhaps on the hottest of days or running the sh*ttest of 95ron fuel.
Get a remap and whack the boost up, use 99ron fuel (v-power) and you'll be able to run aggressive timing and boost with that FMIC. Then it won't matter if your actual boost isn't quite meeting requested because you just won't care. I'd also imagine that the differance between requested and actual would reduce to much nearer the 1psi mark. At which point spending £750 on a Forge FMIC would be pointless!
Assuming the pressure drop IS because of his FMIC and not a simple boost leak, then that amount is excessive. A drop of 1psi is 'normal' for a FMIC.
BUT... Defratos is running the Stock ECU and hence stock boost. The S3 doesn't need a FMIC at that boost, it simply doesn't generate the charge temps, especially in winter. If his logs are recent then ambient air must be less than 10°C, i'd be suprised if he was hitting more than 35 - 40°C inlet temps with a FMIC - I get 60°C!
So, basically he's introduced a pressure loss that the car doesn't need. He's not even offsetting that against a usefull drop in inlet temps because the car doesn't need them either! It'd be interesting to see what CF's he's getting cos i doubt even without a FMIC that an S3 needs any timing correction, except perhaps on the hottest of days or running the sh*ttest of 95ron fuel.
Get a remap and whack the boost up, use 99ron fuel (v-power) and you'll be able to run aggressive timing and boost with that FMIC. Then it won't matter if your actual boost isn't quite meeting requested because you just won't care. I'd also imagine that the differance between requested and actual would reduce to much nearer the 1psi mark. At which point spending £750 on a Forge FMIC would be pointless!
. What you're saying makes sense (a FMIC is not needed on a standard S3) and I'm not planning on splashing out on £700 for a Forge, more like £150-£200 on just the core unit and fit it myself, hopefully just before a remap, should sort things out a bit. cheers for the detailed feedback mate 
) 
