I've had a 2.0st, 1,8 ls, 2.5 V6 sport, 2.5 Gsi and now 2.6 Gsi.
The two I really liked were actually the V6 sport and the 2.6 Gsi the best.
I thought the 2.5 Gsi was a let down as it really didn't live up to my expectations.
After the sport I thought it would be so so much better but it really wasn't
Then when I got the 2.6 i was blown away!
They feel so so much better in every way. Can't say i've been in a 2.6 Sri so I can't comment on them but the 2.6 is 150% the car the 2.5 Gsi was.