A flawed product but all means. Valve guides not drill 100% centre and a few other things. XR9UTE has seen this firsthand so have I. Although if the problems have been fixed? They should be fine even though they don't flow as much as the CHI.
The CHI's flow 680hp! And won the Engine masters comp. www.enginemasters.com
AFD are local to me. Just down the road in Berwick (10 mins from me).
Personally from what I've seen. I'd rather put up with the part change of parts the CHI's require. Although the AFD's require the same parst changed anyway.
The only difference between the CHI and the AFD is AFD flows less and 2V extractor match better but still won't bolt up on car without modifications due to the exhaust ports being 5mm higher.
CHI heads are more a 4V head but built for lower rpm. Well the Engine Masters head is anyway. The 218cc 3V's I have are designed for higher rpm.
A word of advise is to make sure you get the real figures for both heads. I found the CHI head cheaper. AFD had hidden costs.