This 1995 GMC Sierra 2500. http://chicago.craigslist.org/nwc/cto/1207780608.html It has the 6.5TD in it with 190,000. Main things I would like to know are: 1. How are these 6.5's as terms of power and reliability? 2. What would one of these average as far as fuel economy? Any help is greatly appreciated!