I would say go with the Sirio Evo IV Sti and the Sirio 2611 pipe. That motor has very good throttle control from bottom to top and torque everywhere. I ran mine for the 1st time this past weekend and it was easily one of the fastest motors on the track. Won the B-Main by 3 ro 4 laps and was on cruise control the last 10 minutes of the race. Got the bump up to the main and started from 10th spot and made it to 7th place. Not bad considering it was the 2nd time racing my Evo 2 and the 1st time out with the Sirio motor.
Regards,
Speyederjedi