Hi Joe, have you looked into JBS's / Custom Code VVT Attack - seems to claim that it can make a fair bit of difference to performance and driveability by playing with the VVT... may be just sales chat, but not looked in to it enough to comment - read various differing opinions online (as you do)
'The most noticeable aspects of the Custom-Code VVT Attack calibration is the increase in low down torque, this is uncharacteristically maintained though out the rev range'
Also with the VVT Attack Calibration you can see:
1. Improved thermal efficiency means your engine runs cooler and with less EGT this can result in prolonged engine and component life and improved fuel economy.
2. A Substantially smoother running engine both at idle and when on load.
3. The engine is now much more willing to rev , giving the feeling of a larger cubic capacity engine.
4. No flat spots or drop in torque, smooth power delivery all the way to the rev limit.
5. The improved exhaust cam calibration now allows the engine to expel the exhaust gasses much more efficiently, this give a much deeper and sportier sound to the exhaust note.
A VVT Attack car is easily identified buy the exhilarating exhaust note. Even with the standard exhaust.
Custom-Code VVT ATTACK software is available for the following 1.8T engine codes:
AUM, AUQ, BAM, ARY, BFU, BUR, BUP, AMK, BKU, BJZ, BBU and BLZ.
http://www.jbsautodesigns.co.uk/product/3890/vvt-attack-18t