I'm on the other end of the spectrum from you at 6'5 and about 295 but I would definitely recommend getting fit.
There is just no substitute for having clubs that fit you personally.
There is nothing better than standing over the ball and knowing "if this shot goes wayward then its my fault, not my club, shaft, grip, lie angle, shaft length" etc.
Also its tough enough to get good at this game without having to compensate for bad clubs too.