Ok , i thought i'd go have a look round a 34 to see what the factory setup was like , i wouldn't think that there's 'alot' more room under a 34 bonnet than a s14 , i took a few pics incase it will help . Anyways , what does your car do whilst idling? , do the temps increase much under slow - straight driving? (and/or does the temps rise under any other conditions other than drifting?) , think about where the air is flowing while your sideways , i wouldn't think much would get to the rad (especially with some of the clips i've seen of you ) . if i were you i'd be adding some thermo fans on the front of the radiator and maybe some ducting out of the bonnet? .
p.s one thing i did notice with the 34 is that the radiator seals up pretty well against the support so the air that hits it has to go through . pics:
p.s.s : another thing with your thermostat , have you tried another new one? tridon are notorious for 1 out of 5 not working correctly , in my race car i actually wire mine open so it can't give me problems