On Top Gear, the Huayra did 1.13.8 (with cut slicks, as far as I remember) and the Sesto did 1.14.0 (with road tyres?), but it's hard to compare lap times when the track/ambient conditions might have been different.
The 675LT would be a great car to have too. It beat the Sesto Elemento and Huayra. Also, the Aventador LP750-4 Superveloce needs a competitor.