Hi!
I think all Chinese /Taivanese .40 engines use ABN technology today. The only engines with chrome plated cylinder today are MVVS and Rossi. And the MVVS .40 is no longer available!

By the way! Have you tested the Kyosho GX.40 ??? Same as the ASP.40 but with a little larger silencer exhaust opening.
I have used this engine now for two years in Q-500 pylon here in Sweden and I'm impressed with how it works.
It turns a 10x6 (yes, we are only allowed to use 10x6 props in Q-500) RAM at around 14000rpm on 80/20 fuel. Same as the TT.40 SE.
I have three Kyosho GX.40 and they all turn the same rpm.
I was out today (9 degree celsius and cloudy, deck hight about 100-150m) and got 14100 rpm on the tach using a Nova Rossi 4A plug, The 0,20mm head shim removed and using 10x6 RAM prop. Rear ball bearing replaced with a WIB C4, 28x15x7mm bearing (same size as in every other .40 engine) and silencer modified with three metalscrews to hold up.