I seem to remember that it, the central port, was worth around 100 fps in an FAC .177. The RWS 48 shot near 1100 fps in .177 and the HW80 was in the mid 900's with otherwise similar powerplant sizes. I don't have a clue of the true swept volumes, but I did read this in the past. As far as the action laying lower in the 97 vs. TX, when you're shooting FT, it matters not. You have the brilliant side biased loading port on the TX, which means you can mount the scope down on the deck, covering the port, and still load with ease. I once tried to drop my scope and mount on to a 97 for a try out, only to find the port wasn't accessible. I had to use mounts that were at least .5" higher, which negated the offset port. I do think the central port set up is not as nice looking, but it's not that much difference.