The G35 is obviously a great car. Rear drive, powerful, classy, wonderful road manners, nice c0ckpit, option for manual transmission if you like driving a stick. I wonder more about the deal you're giving your brother by giving him your car in exchange for him taking over the payments. Depending on the relationship between the Accord's current payoff, remaining payments and current fair value, that type of transaction has the potential to screw one of you.
If you made a large down payment when you bought your Accord and have a lot of equity in the car, the present value of the remaining payments may be much less than the value of the car. You get screwed. On the other hand, if you made a small down payment when you purchased your car and are still upside down, the present value of the remaining payments may greatly exceed the current value of the car. In this case, your brother gets screwed.
If you agree that the transaction is fair, I also wonder about the remaining logistics. Of course your brother can make your monthly payments, but was it your intent to get the loan out of your name? Will the loan company permit this? If the loan remains in your name, is your brother okay with the idea of making payments for 3-4 years but not establishing or improving his credit? If the car loan remains in your name and your brother misses a payment, how will that affect your credit rating? If the loan remains in your name, how does that affect the car's registration and insurance? Who is legally responsible for what? If the loan remains in your name, can you get another loan to purchase the used G35? How will two loans affect your credit rating and interest rate? To be safe, before you and your brother commit to anything, I would suggest you contact your loan company and make sure there'll be no problems.