The engine mounts you have listed will work just are not as strong as they are cast and doe not have the extra mounting hole where it bolts to the chassis. Yes I recommend waiting for the HPI pipe and when it comes out I plain on changing to it over the Associated I have now. The race clutch in my opinion is just a much better clutch all around! The stock CB is junk with a very poor bearing set up. The CB teeth wear so quick over the Race CB you will go through at less 2 of the stock ones to every one of the Race if not more. All so when the stock CB wears it all so puts a lot of wear on the spur so they have to be replace much more often as well! So in the long run you will come out much better up grading to the Race CB.