There is a thread on STOC going full swing but you have to be a paid up member to see it. I've been posting on it and speculation is rife as to what exactly JamSport do. There is another known alternative to their block mod by fitting Darton Liners. I've seen a website the supply and fit for £1400 inc VAT. JamSport's block mod is £850+VAT so it can't really be the Darton Liner mod. Whatever it is, they will not reveal anything.

As far as I am concerned, until they produce some sort of testing that they have done, with figures as to what limits they have tested engines to, then I will stay sceptical.