The unit on ebay is much better than the one you recommend. It is in high demand and will work with all the narrowband sensors, except the one from Dodge with 2.5V offset.
It has an adaptive control (fuelsaver efie will not work with fast sensors) and a MAP/MAF control (not present in the unit you recommend).
The seller of the unit switched from fuelsaver couple of months ago.
For even higher gains this is the best, so far:
Tuning 101 Control Center AFR
http://cgi.ebay.com/ebaymotors/Tunin...Q5fAccessories