If you remember TSM was based around a 24 psi limit which I considered low boost. Compression was approaching 10 : 1. The cam plays a huge role and the flow numbers that your heads produce. My ESP cammed 109 shifted @ 5400 and red lined around 5800 ( guess). Probably not right but effective (IMHO), I am sure that there was some left on the table. Smaller turbo's have begun to run faster and more efficient than the best turbos of yesterday, technology. What are your hp /torque and times that indicate you have maxed out your combo?