Originally posted by InitialD
True. But like what others have mentioned, the exhaust height plus all the other ports are raised by 0.3 mm if 0.3 shim is added under the rim of the sleeve.
Yep, it will raise all the ports and I could only presume Mr JP knows what he's doing.
As to the overall effect, I have no idea.
I prefer to just buy 'em from the people that know what they're doing. I'm unlikely to catch up to their level of knowlege that separates a good engine from a blistering one.