I have a Leigh D3 dovetail jig, which gets used from time to time - not as much as I would like, but it does get used. I get a little frustrated with the wee little plastic stops for aligning the wood square to the jig. So I started lusting after the D4. But then I noticed the upgrade kit, which is a whole lot less money and hassle than selling the D3 to buy a D4. Has anyoone done this, and if so, how do you like it?