how did you go speaking to an automatic specialist yyc34gtt?
i called a really nice bloke who used to do re4's but has now moved onto amg's and bmw's. we had a long chat about different upgrades, line pressure, shift kits etc.
he said that the main thing that causes flaring and slipping in the automatics is the shift solenoids and or a worn valve body as they're aluminium.
I mentioned that my box was still quite tight, only flares once or twice in a 30minute session of hard driving, and i am planning on putting more power into it. What can and should i do? His answer, nothing. if it's still shifting fine now with more boost it sounds like its in good condition, if it does start to slip, buy new solenoids and possibly a new valve body and it should be fine. The thing he didn't like was upgrades such as line pressure, blocking off pistons (he called them something else) and the other 'usual' one off mods people do, as it puts a lot of strain on other components and will not last unless you do them all, and it costs more than doing the right thing, which is replacing worn parts.