Shocks towers are still available from fibre lyte and yokomo oem are listed on the CML website as being available along with other parts. Stuff like the servo saver parts/ball joints/hubs and carriers and diff parts are still easy(ish)to get hold of. Its also worth a mention that certain YR4 (touring car) parts are interchangable. Get the YR4 manuals form yokomo usa for part numbers etc
If you do a search of ebay for yokomo parts i think a gear adapter is being currently listed, you would then be able to run different spurs.
I would sell some of the motors and get some modern electrics. Stuff is a lot more affordable these days than i used to remember back in the day and there is a lot of quality used electrics around.
Of course if you want to keep it retro then........
Let us know about the shell re-pro by kamtec, I am sure there would be a few interested parties
