Didn't read all the posts but I'll side on the "bad idea" side. While I think taking out a loan so as to establish credit history is a good idea, as you don't know when you'll be wanting to get a house, in this case it's to buy the wrong vehicle. It's a toy, not something you "need".
I'd keep saving and pay cash for this toy. In a couple of years, maybe trade in your car for something new(er)--by having a substantial downpayment, perhaps you could avoid high interest charge even with a high interest rate, pay aggressively, and establish credit history. And look like a decent risk for a bank to accept.