Careful... The 4.0L's are notorious for leaking from the PLASTIC, yes, PLASTIC thermostat housing. The leak often appears to be coming from other locations causing many incorrect diagnosis. I'd look into the t-stat housing before you let someone rip into the engine and rip YOU off.
07 GT Prem: Alloy, MT, 3.55's, Steeda CAI w/Brenspeed tunes, FRPP Stingers, 275/40/18 Goodyear Eagle F1 A/S on SVT Cobras (OE GT500's), 14" shorty, Wheelskin side scoops & qtr window louvers, A-H rear window louvers, SHR honeycomb blackout panel, Sequentials, Hella Optilux Extreme XY fogs, Silverstars
06 V6: Legend Lime, Pony Package, 14" shorty, Sequentials, Hella Optilux Extreme XY fogs, Silverstars