I went from OE Bilsteins to NTR1s recently. (2004 R300K upgraded to about 190bhp.) I considered Quantums but was advised that for almost exclusive road use the NTR1s would be good enough and save a few £££s. I've only managed 500 miles or so but, with a suspension set up - corner weighting etc, the handling has been transformed. I've yet to play with the Nitrons to get a slightly more compliant ride for poorer road surfaces but will wait until after track laps at CLM next month. I doubt you'll be disappointed with either NTR1s or Quantums. Peter