highwayman- you also asked about pistons, hole sizes and bits? with the losi pistons, the larger the number, the smaller the hole. losi pistons are all color coded: white-#60, black-#57, red- #56, orange-#55, blue-#54. if you see drilled or standard pistons specified on set up sheets if indicates whether or not the molded holes have been changed at all. for example, i start with #60 pistons for everything and drill the hole i need with the appropriate bit. the molded holes can vary slightly and drilling eliminated this. occassionally, i will drill the holes with two bits, as ned911 mentioned, for VERY fine tuning; a piston listed as 5-5-6 would be a piston with two #55 holes and one #56 hole, which would theoretically place in the piston in between a standard 56 and 55. the new losi shock tool is a great asset when it comes to doing some bench tuning and testing with things like this.