All of this is really irrelevant to be honest. It all depends on how much money you have saved up and what kind of loan your credit will get you.

You really shouldn't be buying based on what your monthly payment is going to be especially with a 100% commiss job you need to look at what you can actually afford (the actual cost of the car). Also, can you afford the depreciatation so you don't end up upside down? Like Doug Demuro said in his Stinger video, he can afford a fancier new car but he cannot afford taking a huge hit on the depreciation on a new car. I would have never bought my 86 new without putting down a chunk of change to take care of that initial depreciation.