I had the full RS setup fitted last year. Its likely that its slipping due to the weather / temp outside. Mine used to slip when it started to rain in 4th 5th and 6th. but wouldnt when it was dry.

Its not the bhp that matters, its the torque. With a remap, the ST is putting out over 300lbft torque. The clamping load of the standard cover isnt strong enough. When I removed my clutch, it was mint with virtually no wear.

If you handy with a spanner, you can remove the box on axle stands. Theres no subframe to remove etc. The RS setup is around the £500 mark for parts, thats clutch kit , flywheel and slave cylinder.

By the way. The RS clutch setup is cheaper than the ST setup !!!