Yamaha DTXpress/DTXplorer/DTXtreme

This is really embarassing. I just won a used DTXPRESS kit for $585 on
ebay, shiping is an extra $90. But I thought that I was bidding on a
DTXPRESS III.

This kit is for my two sons, who are novice but serious drummers, to
use in church. Is a DTXPRESS worth that much? Used DTXPRESS III's
usually sell for around $750 on ebay, and shipping is around $50.

Did I screw up badly? What does the DTXPRESS III have that will be
missing from my kit. Will the pads be ok? single or double trigger?

I couldn't find any specs on yamaha's websites for the older kit.

Here is a DTXPress on ebay current going for $455 with 2 days still 
left on it..

http://cgi.ebay.com/ws/eBayISAPI.dll?
ViewItem&category=64444&item=7325929101&rd=1&ssPageName=WDVW


another one at $385 with 3 days left on it.
http://cgi.ebay.com/ws/eBayISAPI.dll?
ViewItem&category=64444&item=7326188041&rd=1&ssPageName=WDVW


so the price you got it for doesn't seem too off.
about the shipping, I just bought a dtxpress III special from ebay
and 
it costed me $90 bucks for ground shipping.