It's your money, do what you want with it. Doesn't matter if you type at 60 or 160, we all like to own nice products and with that in mind, I'm pretty sure that's why a lot of us here on GH own a lot of the expensive products that we do.
I type at a fairly high WPM and me buying a HHKB for example and you buying a HHKB, there is literally no difference, I'm no better than you because I can type higher/faster on my HHKB than you.
At the end of the day, practice makes perfect, none of us started out typing at these fast speeds, it takes time, I've been typing since I was about 12 and I'm 24 now. I remember back when I got my first computer, I was typing with one hand (lmfao) and looking at the keys constantly, oh how far I have come.
Just buy what you want, practice and then that's that.