[axsaxoman]

I think we are getting to far into modern car technology ,as I have yet to see a saxo with a MODERN type turbo or anything like real boost control or motorised throttle and as far as emission regs --well that just doesn,t compute with after market tuning .

I am guessing the reason for the lower comp ratio with the AMG is the 340 bhp ,so they needed more volume to fill with micture to get the extra power .
.another one of these compromises --bugger cv volume means more burnable mxture so should give more power for same boost level and- keeping ex gas temp down to stay awya from the det on modern low octane bio fuel
-but its all a compromise.
I quite sure if they could run less emmison friendly fuelling then they could also run higher comp ratio ,as the extra richness would cool the burn .
as for EGr ,that just buggers up everything as far as power goes .
a compromise

its all these sort of things that makes believe that after market engine tuning is very close to dissappearing -due to costs involved in doing anything major to the latest era of engines .
which is also why i think the saxo will become a classic as it was probably the last car that can be tuned simply .
I would love to develop the DS3 engine ,but i don,t see the market for it .
even the non turboed ,non direct injection engine has a lot of advantages over the tu 5 ,but needs alot of things changing to make it release the extra potential it has over the tu5 .