there is a separate thread for evo iv's. gears are not interchangeable between the two, but suspension parts are compatible. not much else can be used. Gears are made from graphite material, so they will be much more durable than tt01. evo's come with oneway stock. if you dont like using one ways, it might be a pain in the neck sourcing parts for a second diff or, finding the elusive tamiya spool.