Today I installed a new Tech Pulley sliders to my SW-T600.
Original weight is 28gr. I ordered 27gr Tech Pulley sliders.
Here is a difference. Speed vs Rpm
Speed Roller Tech Pulley
60km/h 3700 4000
80km/h 4250 4500
100km/h 4800 5000
120km/h 5800 5500
130km/h 6250 6000
140km/h 6800 6500
Under 110km/h rpm's are little higher than with rollers
From 110km/h rpm's are about 200-300 under.
Acceleration improved dramatically.