I asked this in another thread but I think its a valid question for its own little thread. (you may disagree).

My father in law and I both have Cobra drivers. Mine has a shaft that is too flex'y and his is too stiff.

Can we get the shafts swapped (don't want to swap clubs as his is illegal) - if so how much is it likely to cost ?

Thanks for the advice. 

The pro at my club charges £5 for shaft extraction.  You can rfeit yourself if you want as the are just epoxy glued back in place however I doun=bt if they would charge much more than £10 per club for the whole job.

The one thing you do have to watch for is that the shaft diameters are the same and that,  if you do not have the clubs regripped at the the same time,  the grips are in the correct position

About 10 quid, maybe a touch more if it includes swingweighting. To swap a shaft from one head to a different type of head, and for it to play to the same flex/feel you will have to check the length, the insertion depth, and the BBGM, otherwise a player with a very astute sense of feel may notice that it does not play exactly the same. Most Cobra drivers are .335. 

Totally agree with rgusa, but just to add a little bit nore even within the same company there is no standard. If you measure three "same" flexes from the same company you are more likely to get three different values.

As has been said here before "S" should stand for Something, "A" should stand for Anything and "R" should stand for Random. I will leave you to amke up names for "X" and "L".