The clutch bells on all these kits are a two piece design, the gear teeth are pressed into the bell (this is why we do the bell trick), the clutch bells themselfs are alot bigger than most standard 8scale bells and most all standard 8scale clutch bells will fit inside a NTK one, the NTK bell offers more bite to the bigger teflon shoes but I believe even the standard 8scale 2 shoe teflon ones will work too with maybe a bit of a inside trim. With the two piece bell, gears/ratios can be changed, I have put on some 14 tooth gears on from the factory 17 tooth. Your shoes look worn some but look good/fine to use, a deeped spring grove can be filed/cut and the spring shortend a bit (1/8+) if needed no problem. The blue headed kits were the first batch/versions, the purple head kits were all later versions. the stock sport tune pipes have a long header going up inside the can, all the way up and stop at basicly the stinger, by shortening the can you can change the way/speed the exhaust waves come out the header hitting the end of the can. The first batch of pipes were all welded so they are hard to mod, the newer/later pipes use machined ends/parts and are easyer to mod. The factory rear brakes work excellent if they are setup with the modded throttle linkage (the factory setup is JUNK), if you want to try diffrent brake disks I will suggest the OFNA 8scale ones.

Some times guys have made the mistake of putting the plastic version electric ETK gears into the nitro NTK trannys which uses DELRIN molded gears, they both look the same black colored gears but are not, if you drop each gear seperatly on the concrete floor you will hear a diffrent sound/pitch as they hit the ground... delrin VS plastic.

I do contract work in the film/entertainment/sports industry I work on/building things for Disney, movies, film sets, props, I am a bodyman by trade, like doing some mech and specialize in heavy collision and use to build custom cars/bikes on the side.
http://www.cardomain.com/id/kazzoom

Well I guess I'm kind of semi retarded... oops... retired now. Besides my own little one man band/show operation I contracted for a few diffrent shops in the past but now at my stupid old fart age of 43 I now mostly do projects for...
http://www.fdscenechanges.com/index.html

In my personal life I have usualy always learned things the hard way so... let me give all you young bucks that read this one more great big tip in the game/hobby of life... DON"T HOOKUP WITH A STRIPPER... oh YES... stripper BAD... R/C good... very good.

Now BEER is my new love/hobby... 6 pack a night lol.