Lets put things into perspective.
A $50k car will cost you around $760/month on a 6 year used car loan at 3% (assuming you have stellar credit) Additionally you will pay around $4000 in taxes at registration depending on your location. At the end of those 6 years you will have a dated car worth maybe 1/3 of our total investment and most likely costing you more due to high cost of maintenance on a high performance car.
Why don't you invest what you would have spent on taxes/registration...say $4000 into a moderate risk mutual fund (~5.5% return) then $760 every month for six years then stop the contribution. Let that money grow until retirement age (65). At that time you will cash out over half a million dollars.
Investment calculator
On a side note...when I was your age I would have been embarrassed to be living at my parents house. But thats just me.