Don't know how accurate this is but a good reference none the less.
Came across these on the net and thought it'd be a good idea to stick it in one place.
I can't vouch for the authenticity but looks to be a worthwhile difference if you are considering tuning a JCW car and you can get it reasonably priced.
Waiting on RMW and Thumper stats - eViLDon't know how it can be a moot point really. The best heads flow more at high lift.
All the stats I've found seem to measure at 0.4 or 0.45. Your own TPR2 spec quotes a max lift of 0.41 int & 4 exh
Here's what I've found.. I've calculated the %age flow increase over stock from the numbers published to give some comparison..
Int 3.8% @ 0.4 Exh 4% @ 0.4
Int 22% @ 0.4 Exh 33% @ 0.4
Int 14.3% @ 0.45 Exh 36.5% @ 0.45
Int 25.7% @ 0.45 Exh 34% @ 0.45
Int 11.4%, Exh 18%
Int 9% @ 0.4, Exh 25% @ 0.4
Can't find any stats for a Thumper head though. Can you share?