If you have ever personally driven a properly tuned car with the GT28RS turbos I do not think you would be calling them laggy. I had these turbos installed, and I never had problems with lag driving my car. The boost response of the turbos was great as long as you didn't expect them to spool at 2K RPM or anything. I posted my dynos with them and even on mildly ported stock manifolds I had a very good powerband. They were very comprable to what the 2530's with stock manifolds were doing in terms of both power and lag.
If you want to see lag, you should test drive a Supra with the HKS 2835's and the .73 a/r turbine housings. ;)
