Certainly don't need to lower CR's like most do, even for some 330-350 tunes, better ecu control, or rather better injector control has played a massive part in tuning, esp over the clockwork L1/6 etc.
I'm on greys with 0.97% CO with 137PPM, with just under 190,000 miles on the bottom end, but I do flush every oil change, I'm only running 17/18 psi at the mo due to wear, but yes 380 easy on a .48 t34.
tabetha