I had Tein RA's on my WRX. They were very, very nice...full aluminum construction, inverted strut (not for 240's though), threaded shock body, pbm, 45mm piston, 16-way damper adj, perfect fit (had all fittings for brake lines)...the whole shibang! My only beef was that the dampening adjustment was hardly felt unless I REALLY pushed the car and the ride was rough. But that should be expected with any 'race' coilover. Other than that, I had no complaints.
Oh, and stay away from the Flex unless you like gadgets and want a 'comfy' coilover.