I've never heard of one "warping." Hopefully there isn't a damaged crankshaft. Replacement isn't hard if you have the tools to do it. Remove the radiator and belts after draining the coolant, remove the crank bolt, remove the crank pulley. I would recommend replacing the front crank seal. Reverse to install. The hardest bit of the equation is the removal of the crank bolt. If you have access to a 1/2" drive air gun, you can break the bolt loose, but be careful not to damage the AC condenser core or turn the bolt out so much that you end up getting your air gun caught between the bolt and the condenser core. I believe the crank bolt head is 27mm; 1-1/16" should work, IIRC. There are slap-hammer type tools to break the bolt loose as well. The crank pulley can be carefully removed using two pry bars or, if you have one that fits the tight confines: a gear puller.