Yes I can help
Yes alot of the M parts (almost all except chassis parts) are interchangable with older M's, like suspension shocks, wheels, bearings, dog bones, diffs...infact I think the diff taht tamiya recomends for the M (manta diff) fits like every car, so...
Tiny R/C if you're able to get the GPM shocks I'm definatly interested. I think that GPM only sells them in pairs can you confirm this? or do they also sell in sets of four? Not clear on how GPM works.....