Some combination of parts from Ferrera, aint cheap though think I paid around £289 or something like that. Havent got part numbers to hand sorry. Tomei specifically said not to use their springs, which is nice of a tuner not to sell you something of their own. I think because they said it may bind and lock out the cam. Could be the same issue with the standard one but then if its working people dont moan, yet their could be room for improvement, like keeping better control of the valves and therefore creating more power.
Nad