The Porsche is just to satisfy the need for speed.
I lived in Germany for a couple years and drove pretty fast on the autobahn, normally 110-120mph and a few times up to 130mph. It really didn't take long to get board of it.
But, if that's what you want to do, go for it. It's your finances that you'll have to deal with if something doesn't quite work out in the future. Spending more money now just for a little fun won't help you much for realizing your dream in the future. Spending a little less on a different car now could help you build your savings (adding more with the accrued interest along the way) and could end up getting a nicer boat later on.