http://www.ebay.co.uk/itm/RARE-ASTRA-2-0...SwNRdX29N9
Stumbled across this just now, 240bhp and over 400lbft ! I imagine it will break gearboxes pretty swiftly with all that torque
No mention of how it has the extra power and torque
About the cheapest bi-turbo I have ever seen too