its probably the GT25 which goes for like 1400. Its actually huge. My friend just got one, I think the thing is a monster. Good luck, I really don't think its a t28. I think all the GT series are hybrid turbos but all seem hot. I think its a t28/t04s.
I think I still like the rev hard. My price on the rev hard was 2850 and the guy told me he would upgrade me to ball bearing for 500 so total price is 3350.