Thanks for all the kind comments guys
Sorry for not posting earlier on this - got back quite late last night after being stuck in a thick M6 jam
Then today, been really busy catching up with work.
Well, there were gains, but if I'm honest, not as much as I'd hoped. Bearing in time that the last time the car was mapped, it made a peak power of 270.1bhp. This time it made 270.6bhp (ie no change). BUT, the last time it was mapped, it was a very cold day whereas yesterday was around 10C warmer in the workshop. All things being equal you'd expect a little less power in warmer conditions, which indicates that we did get some peak gains. More interestingly, we got quite a lot of gains in the 3K-6Krpm area. This surprised me as I thought I might gain some top end but perhaps lose some midrange. Paul commented how he needed to add quite a bit of extra fuel in this rev range, which shows there were real gains. It also goes to show that the frequently heard claim 'a bigger bore exhaust slows down gas velocity and loses midrange torque'
is complete ballocks!
Paul thinks that the reason we didn't make much more peak power is simply that the A3 cams are pretty much maxed out at this kind of power on a 2L capacity, which means that the extra flow offered by the 3" exhaust couldn't really be used. Having said that, as some of you know, my plan is to add a bigger bottom end later this year (probably a 2144cc through boring but not stroking). Then, the exhaust (and all the other bits) will really show their mettle.
I have got any dyno prints here but will get Paul to email me so I can post them up later