International 9400, what to look for?

I'm going sometime next week to take a look at 3 International 9400's. Only looking to buy one, but there are three to choose from. Two have 10 speed FRO15210c, and on has a FRO16210c. Just a little different load ratings. All have ISX's(450hp EGR's I think.) and 3.58 rears. They're are the smaller stand up sleepers and I believe the wheel base is 210 on them. Mileage ranges from 348,000-423,000. All are 04's. According to them, they've all been recently dyno'd and can provide documentation of it. What else, when it comes to these trucks should I look for? Only truck I've ever owned was an 03 Columbia, so I really know nothing about these. They're cheap, 17,000 each.
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Thanks for the replies. I've decided to go another route and not buy another truck. Back to letting someone else worry about it.