Welcome Jordan,
While I can understand your desire to own a GT40 you might consider a couple of things first before looking for a monthly plan.
1) Put some effort into developing high quality writing skills and learn to use the spell check button. These two things will assist you on your GT40 quest. While there are many people in this world that are successful without competent writing skills, it is a great asset that can translate into dollars and these dollars can then translate to a GT40.
2) Consider running the numbers of what a monthly plan for a car would be, I see some completed cars (GT40) for sale around the 60K (conservative) and up, and kits for less. Lets pretend you can put 10K down and finance 50K (that is as a 17 year old with what I am assuming has no credit experience and an hourly job). Continuing on, with a term of 60 months, an interest payment of 8%, the monthly payment results in $1013.82. All of these numbers are conservative and I am sure you can find cars for less but it illustrates a point. I at an older age than you would have a hard time paying $1013 a month for a toy and I have a decent paying salary. But maybe you have other financial resources, which if true then that is great.
3) Focus your late teen years and early 20s into creating a career that can support whatever you want, be it GT40, a family, travel, a house, etc. While you can always create careers at anytime in life, using your late teens and early 20s provides some of the best years to do it with the minimal amount of responsibilities (like car payments, child payments, house payments, a wife that spends a lot).
What I recommend now to quench your GT40 thirst is:
1) Read all you can about the car and supporting components
2) Join a car club where you can experience cars with others but you sidestep the cost of ownership. Sure the cars are not yours but you can learn a lot and get some enjoyment out of meeting new people
3) Find a part time job at a mechanics shop, there you can learn how an automobile works and after years of learning purchase a GT40 kit to build
4) Focus on building a career that can support an automotive hobby…. It is extraordinarily expensive
I was 17 once so I know that these pieces of advise are not what you wanted to hear and there is a good chance that they may not be heeded. With that said, I only know now that by doing some of the things above I will someday be able to purchase a GT40.
Kevin