not really so weak. this engine is stronger at 4500 rpm than the ST1300 and hp is likely higher at that rpm as well.
CTX1300= 78.1 lb-ft @4500 rpm
ST1300= ~70 lb-ft @4500 rpm
And I am guessing, after looking at the ST torque/hp curves, that the CTX1300 and ST are the same torque and hp at 5252 rpm (the rpm where torque and hp cross each other) with torque on the CTX just starting to fall off a bit and the torque on the ST still climbing (hp for both are still climbing at that rpm). the ST peaks at a higher rpm and climbs faster but starts off lower than the CTX. I think the CTX might (IMHO) beat the ST off the line from a dead stop, slightly, and the ST would quickly catch up and pass. This, of course, remains to be shown but the numbers seem to support these thoughts. IOW- the CTX will launch faster due to low end torque, but the ST will accelerate faster as rpm builds. Assuming that you really want to try to race each other... not really recommended cuz the CTX would loose that race unless the course was real short... like half a block or less, maybe a wide intersection.
maybe someone who buys one first can go to a track or someplace where they can get the dyno numbers for a CTX? Then we'd know for sure.