I didn't think about looking at the Itech 4000. I thought they would cost way more than that. I will check it out. Thanks!
XTI or most of the budget amps available today, for high power subs is not ideal at best for many reasons, the XTI is a great amp but not for heavy sub duty. Keep looking on eBay and craigslist for itechs, I've been following eBay for a long time and to get that price ($1000 for IT4000) would take awhile, the 4000 usually goes for $1200-1300, the 6000 $1500-1600 and the itech 8000 goas for $1800-1900. If you find an amp that has particularly low hours or still has some warranty left on it then the price would go up. Average hours for the used amps is around 2000 hours. You can find great operational and cosmetic condition amps with more then 30,000 hours on them and there are those with low hours that have taken much more abuse then they should have so do your research thoroughly.
As a general practice when you buy a used itech you should ask for the amps serial number and give crown tech support a call to find out the specific amp service history.