i've got 260deg poncams in the 33gtr,
we put them in with the standard turbos and you could really feel the diferance, the power would keep going till 8500rpm we only stopped because it was a stock motor.
now once the car is had its final tune (in a couple of weeks) we'll take it out to 9000rpm
and a bit further down the track once we have money again and put in some valve retainers we'll bump it up to 9500rpm and 27psi and try to crack 350awkw!
as for if you should get them thats a yes in a big way.
as for idle, sounds a bit like a rotor! barb barb barb barb!