I guess it depends on who's doing the signing. I think Hendrick or Roush would favor Kahne while a team like Stewart Haas would favor Harvick. If Harvick continues to run well this season then I see him re-signing with RCR but I could see Kahne leaving if he landed a better ride. If the #5 car comes open after the season then I could see him going there. Who knows with Mark Martin, he is the Brett Favre of Nascar.
I think I would lean towards Harvick because of his exposure (with his own teams) in Nationwide and the truck series. I think they are fairly close on driver talent, Kahne is good if you give him the right car as is Harvick although I think Kahne might be worth a little more from a marketing standpoint.