Yep. I found the same with my Sirio PL5000 magnet mount antenna versus both the K40 and the Wilson 5000. Better RX and TX range. All that I didn't really care for was the RG58 coax that comes with the Sirio magnet mount, the PL145. I just switched mine out to Andrew LMR240. Worked very well and was easy to install on the magnet mount as well. Some good RG8X would work just as welll I am sure. But when you have a lot of LMR240 coax laying around, might as well use it!!
Anyways, I did find that the Sirio performer 5000 did a better job then the Wilson 5000. For that matter, the Turbo 5000 and the 4000 model as well with the long whip, all 3 antennas worked very well for both local and DX comms.
I even modded one of the older Sirio 5000 antennas. Drilled out the hole for the whip and cut a 102" whip down. Made one stiff antenna. Stayed straight at highway speeds no problem! But it wa heavy! They now make the whips a tad smaller in diameter than they used too. 3.5mm vs 4mm I think if memory serves me right. And the older ones with the larger diameter whip did work a little better for highway use IMO.
None the less, one of the best antennas I have used besides a 102" whip or a large coil type antenna that was almost 8ft tall, (old MM Big Jon?). At any rate, they are good antennas for what they are and do a good job no doubt!!!