With the 285kw Clubsport HSV have made the stock internal LS1 just about as good as it can be. The headers are a superb design, the MAF tube a great improvement, and the tuning a quantum leap forward over older HSVs. Good enough for 213rwkw. There is still plenty to be had though, as with a carefully implemented Mafless Tune we were able to extract a C4B killing 241rwkw. All this with stock exhaust system, stock air filter, and less than 500km on the clock!