Ask the dealer for a FULL Oasis history report, this report shows everything that was done under warranty.
Start reading up on the 6.0, they can be great motors if you know what to look for. Try to find out about the maintenance from the prior owner, if they neglected it, you may end up paying for it.
Here is a good start for you.
Things to consider about owning a 6.0L
As already mentioned, take some kind of monitoring solution with you to the dealer. Check the ECT/EOT delta, the FICM volts, find out if there are any mods done to the truck (EGR delete, studs). If possible, have them confirm the fuel psi at idle and at WOT, if it falls below 45psi you risk damaging the injectors. FICM volts should stay above 46v at cranking and KOER.
Ask them to NOT have the truck warmed up before you get there. Your gonna want to start the motor cold, check for smooth idle. Rough idle could mean FICM issues, or injector stiction. Check for white smoke out the exhaust, could mean EGR cooler failed, FICM issues, and/or turbo seals.
I know I'm forgetting alot, others will chime in.
2004 F350 CC DRW King Ranch
X-3 tunes by DJ'S,QT,GH,ID. Gryphon FICM tunes, ARP studs,Stage 1turbo,ATS coolant recirc lines,Swamp's 48v ficm,coolant filter,AD2,Snow Perf stage II,EGR delete,4" turbo back straight pipe,S&Bintake,Quad "A" pillar autometer gauges,Suncoast Tri Disk Conv.,Billet input shaft,Suncoast superduty rebuild kit,Trans-go shift kit,Mag-Hytec trans pan,CFM+ elbow,ccv mod,15K reese 5er,17" LCD TV/DVD,Cobra 29 Nitewatch CB