This is for the Defy 2015 - With the SL you get these in carbon - wheelset (save 250 gms over the non ISP model, stems and handlebar. You also get a supposedly higher grade of carbon for the frame. All in you save 0.5kg over the non ISP model. There is no equivalent in a non - ISP model. If you want the carbon goodies it's only available in the SL range ie. integrated seat post.

I haven't yet optimised my seat height yet - i forgot to take a measurement of my roadie i sold to make way for this new bike. So during the first few rides, instead of bringing a multi tool to adjust my seat post, i'll be carrying a hack-saw for the ISP?