Yeah, but since you have no control over how much the restrictor slips the clutch, it can damage the clutch if you aren't careful. I like the concept of the restrictor, but I perfer to leave it out and take control myself and pay the consequences if I screw up my driving.

 

I have the same sounds you described when I let off the gas between 3500-2000 rpm. everyone I talked to said its normal decel noise...