yeah its a completely different size on the head gasket part.. literally if you just layed the 3.3 on the block... the screw holes would be very far from the 2.5 holes.. just plan on going 3.3 ... the 2.5 was so utterly underpowered IMO that it wasn't really a good engine for almost any vehicle.
Yup no problems at all. Super easy...I just sold one to a your buddy of mine to drop in his 2.5 T-Maxx. I would say clutch and all a 30 minute swap over.