Ive got a dilemma..
Get the 300 'cause it sounds like a car you can enjoy right now. You'll still have the wagon project and you can get to that when you get to that. The 300 might be a "Catch & release" kinda car (I used to do that with girlfriends) - I say get it, enjoy it and hopefully someone will come along that has to have it and you should get your money back out if it.