I'm 105kg & 192cm and mainly use the iS76 with 5.8 & 6.8m Warps (also used 5.4 & 6.4 warps, worked nicely). The iS76 is 81 ltrs and does have a wide-ish tail, but it has a thinner profil C/W the 07 iSonics to compensate, dont be put of by this as it works really well. In practice, it does'nt feel like a wide tail at all. In choppy conditions, the iS76 behaves well. For slalom, it has good upwind for "figure of 8" races (goes better upwind than my previous Sonic 90 & 100). For GPS speed its fast for sure, I'v only been out on it a few times in gusty, choppy & square/tight conditions and I'm just shy of 37 knots v-max. In perfect broad flat water, I'm confident it will hit 40k (I hope). I'm very much a rookie and a better rider will take it higher. We've got a gale hitting the UK tommorrow, so I'll be on a mission with the iS76 for max speed!!