the only "bad" thing i've heard about the KNN filter is that there is a possibility of clogging up the MAF/MAP sensor due to the nature of the KNN filter (oil based). That said, SO FAR NO PROBLEM!
For our week-long test we drove the 275hp 3-litre diesel twin-turbocharger model which still manages to cover 0-62mph in a brisk 6.4 seconds while boasting effortless overtaking power. The diesel is also very quiet, more than one unwitting passenger asked the fuel type during our loan. All engines are mated with a six-speed automatic transmission. Jaguar Drive Control adjusts the responses of the accelerator, gear shift responses and steering for a more sporty experience. It also tightens the seatbelts, a neat trick which sets the pulse racing a little faster.