i can answer that question because I was playing with an R5 with a regular TM stock shaft 3 weeks ago. 10.5 degrees set up for a draw bias.
I was in love with my R5 - it straightened out any attempt at a fade or slice, made a lovely sound, and thumped the ball a good distance. But in the last few months, i'd noticed two things: firstly, a tendency to pull the ball to the left when trying to really go after one, and second, I was hitting the ball a bit high. This meant that when I stood on the tee and really boomed one, all my playing partners would say "great shot", then when we walked down the fairway i'd be no farther on than them even though on the face of it they'd not made very good contact.
After a swing analysis session and some advice from a pro, i bought a Geek DCT driver with a stiff shaft (after some great reviews on GM). I bought a 9 degree, but that was actually too sharp for me and they let me exchange it for a 10.5. The result... at least 15 yards on my average drives, and more on my best ones. On Friday i eagled a 280yard par 4 with a 6ft putt - I'd never been able to drive the green before.
So the right driver for you can definitely eke out better performance from your swing - but, I guess, only if your current R5 is NOT set up right for you.
Go get your swing analysed where they have launch monitors that accurately measure the launch angle and spin on the ball when you hit it - if nothing else, i found it very interesting feedback.
