Thanks Abz, PM in reply.
In relation to the above comments re a remap, after having mine done I had no problems at all, then about 6-8 months after I started to get the occasional engine warning light flashing on and off, hence why I couldn't take it back to Reddot.
That was well over 2 years ago and 50,000 miles, I live with it as it is a rare occurence.
Generally my stilo still drives great even at 139,000 which has just ticked over, pulls like a train when you floor it, the warning seems to come more often on lighter throttle but when going up an incline and mainly in 3rd gear, read into that what you will.
I'll try a new overboost valve & piping and maybe MAP sensor as they are only £30 and see if it makes any difference, other than that it can stay the way it is LOL.
If anyone is interested I priced an OV from Fiat today - £57.14 +VAT!!!! apparently their prices have gone up due to the Euro, mmmmmmmmmm