QUOTE(BikerGran @ May 4 2005, 06:32 PM)
Wasn't Slick50 but another one my mate used in his Guzzi California - think it was something like ZX10? (cept thats a bike!). He used it when he did a long trip with his mate on an identical bike. Both had been serviced for the trip by the same garage, and he found his acceleration better than his mate's, and also considerably improved fuel consumption.
The interesting thing is why the manufacturers have never managed to prove it.
Your friends' experience would be good evidence, but it would need a similar test to have been done beforehand and proof that the riders' styles and techniques were identical. I get better acceleration and fuel consumption than my old man when I drive his crappy van (to his constant disgust), simply because I understand how a gearbox works ....