hi Roel,

For me if track grip is low (irregardless of asphalt or carpet) i try soft springs (Tamiya Neon yellow front, Neon blue rear). If grip goes up, harder springs.

Tires I usually run S grips all around in asphalt. Key is to use traction compound. On carpet, M-grip all around on low grip, then when grip level goes up might need to go S-grip front to remove traction roll. Hard inserts front, soft or hard inserts rear.

Just some more M05 tuning items. Hope these work for you.