upgrade from JMW 10 to 10.5 fpr my VPI Aries 1

Are you thinking about the 10.5 or the 10.5i? As noted in the VPI site, the 10.5I is a longer arm and its armtube is not compatible with the 10.0 or 10.5 base. At least the base would have to be repositioned. The 10.5 armtube IS compatible with the 10.0 base. Some time ago, VPI offered a good deal ($300) for a 10.5 armtube if you sent the 10.0 armtube inexchange. I did this, and the 10.5 armtube was quite an improvement sonically. So yes, if you can find one of these armtubes, you will enjoy the results, IMO. Dave

It's certainly possible to upgrade in the sense of buying an entirely new arm, just that the 10.5i armtube will not work with the l0.0 base, or so says the VPI website.

If you're ending up with a whole new arm, then yes it should be a substantial upgrade. Good luck, Dave