Especially since you already have the Federal ECU, I think you're making a mistake to switch back to 4-wire. If your VX is in decent shape, it should maintain good resale value (unless gas suddenly gets ultracheap hahaha), and it will be worth more to the next owner with the right sensor. And it will also save you gas, in the meantime.
I would look for the L1H1. I suppose the L2H2 will work, but I think you will have to put some extra effort into wiring the connector (instead of just plugging it in).
If you look around, you should be able to find the L1H1 for $150-200. Maybe less.
Here's one on eBay right now for $177, shipped:
http://cgi.ebay.com/ebaymotors/HONDA...spagenameZWD1V