I'm surprised the SR isn' better in fact. However, what you're saying is that speeds and fuel flow match but that's with gear down on the SR and reracted in the TB I presume. How does the TB perform with it's legs down? The Commander basically stops in its tracks when they're lowered!
Well it just proves that whatever the SR picks up with a better body it then throws away on the dangly legs. This is of course totally contrary to what Cirrus salesmen tell you; they claim their fixed gear loses 2-3kt - this is complete total b00011ocks. Well, it may be true at 70kt
The TB20 drops from 140 to about 125kt when the legs come down. That's a LOT of horsepower!
TBH if I didn't have the dangly legs I would like a speed brake. The legs come in very handy at times. The only problem is that while a speed brake can usually be activated anywhere below Vne, I have to be below 130kt to lower the gear. A landing gear that can be lowered at Vne would be a great advantage.