Walt and I had the chance today to directly compare the SR20 and 260se on a cross-country flight. We flew the same course within 10 minutes of each other, same altitudes, using the timer/trip statistics functions of the GNS430 to keep track of things. Here’s how it went:
Departure airport O22, 2110 feet MSL, density altitude 3300 feet; destination MRY, about 250 feet MSL. Distance flown: 112 nm GPS direct for both of us.
415WM (SR20): TOW about 2850 lb; full throttle to 6500 feet; cruise 22"/2500 rpm at 6500 feet (check your SR20 POH for % power).
8367E (260se): TOW about 2700 lb; full throttle (2625 rpm) to 3500 feet, then 25" or max mp and 2550 rpm to 6500 feet; cruise 22"/2500 rpm at 6500 feet (approx. 70-73% power).
Trip times (GS > 30 kt): 260se 49’42"; SR20 46’25" I was hoping there would be a brisk wind down the runway at MRY so my GS would drop below 30 while I was still a mile out on final 
but it was not to be!
Average GS: 260se 135.0 kt; SR20 144.7 kt
Maximum GS: 260se 164 kt; SR20 180 kt
Indicated airspeed samplings during cruise: 260se 135-137 KIAS; SR20 140 KIAS. Note: the ASIs are likely to be calibrated differently.
GPS groundspeed samplings during cruise: 260se 147-150 kt; SR20 156-157 kt. My 260se doesn’t have altitude hold and tends to have a slow pitch fugoid in cruise with the autopilot on, so airspeed varies more than in the SR20.
Descent: at or near the bottom of the yellow arc on the ASI
Fuel consumed: Let’s not go there, OK? I didn’t buy any because it’s so #$@&*! expensive at MRY, but past experience suggests the 260se uses ~30% more than the SR20, in proportion to their horsepower.
Discussing this afterwards (do these two guys need to get jobs, or what?) we concluded that while the 260se got to cruise altitude 3-4 minutes sooner than the SR20, the SR20 gained a large amount of ground during the descent. The 260se’s yellow arc begins at ~143 KIAS, while the SR20’s is way up there near 165. This a >20 kt advantage!