Ok lets get a few things straight here;
1) There is no K03S (As confirmed by KKK (Borgwarner)) themselves, this is a myth. Basically tehre are two variants of K03 used the early one and the later type, which has a different turbine layout and a different actuator for the slightly higher boost pressure.
2) The max bhp figure is not important, as I could have a boost spike that would show 300hp but wouldn't mean a dam thing.
3) Look at torque, not at hp! this is what's important in everyday driving.
4) What is important is the gain over standard, so Jabba quoting some of their max figures acheived is not representative and is proven in a PVW feature where they made nowhere near 225 or 235 hp! No doubt about it Jabba do get good figures, so you can't take that away from them, just don't expect what was acheived on one car will be the same on yours.
5) The K03 is only rated for around the 220hp mark!
6) The S3 engine has many items that are different, but mainly ECU, Turbo, Intercoolers and Injectors.
7)I would expect to see more than 180 from a chip, as most tuners quote from 190-210hp, but again this can depend on your car.
500 pounds is reasonably cheap compared to some of the other options out there, but that doesn't make it better necessarily. I could of saved a fortune on my chip if I'd gone with someone else, but I wouldn't change it for anything as it has proven to have made my car very quick indeed.
Do your research and decide with your gut.
