My 50mm item is now coming off the car, GVKs test prove that its not worth it on that state of tune. 42mm for me now , handy i have a polished one in the garage. I agree that really we need same day and sam engine temp and fuel to test, but without testing on different heads and different cams e.g. A car like IanBs or Grahams i am not sure if we can apply the same results to any car. Varible inlet sounds interesting but if the 50mm only gains 1 bhp on GVKs car is it worth bothering to make one Also where abouts in the rev range do you want it to switch over looking at the graphs all i can see is 6200 which makes it pointless. ( I am not exactly sure how the schrick items works tho ) Thats not to say that if there is any modern cars that could be robbed for donur parts they could perhaps work better , but due to pulse tuning it could be hit and miss. Wonder if there is any honda or ford stuff that could fit ?