Unless you are going from a Driver that does NOT fit you to one that DOES fit you then it is a waste performance wise. Of course having something you like is never a waste so if you have the money and want it then get it.
I've had 4 drivers in my life. First was a Lynx driver that came with a set (crap) but got me playing. Second was a TM 580XD that I bought off the shelf because it was the biggest I could find and me want hit ball far. Third was TM '07 Burner. For the first time I actually hit a few drivers first and picked this one but there was no fitting. Finally I got tired of sucking and did a fitting. I settled on a TM R9 Supertri and the rest is history. I now have it set up exactly the way I want it (movable weights and adjustable face angle) and for the first time I can say that is was a well spent $300.
So the moral of the story is if you don't get fit, understand that unless you get lucky (new club just happens to fit you better) then the money spent is only for your personal satisfaction that you have the Driver you want. If you are looking for performance improvement, do a fitting, get the right flex (easiest part), face angle, loft, kick point, center of gravity etc etc etc. Keep in mind though that the fitting may result in a recommendation of a club other than what you "want" so align your purchase with what matters most: Performance or Personal Satisfaction.
Good Luck!