Noted. Several, but not all, of the clubs I'm referring to already have aftermarket (stiff) shafts. For example, the $40 TM R540 at Global Golf has a Grafalloy Blue, which from what I can tell, is a well-thought-of shaft.
I had the Grafalloy Blue in an R7 460 & I thought it was a horrible shaft for me. As I mentioned earlier the only 2 I have found which work in a driver for me are the Prolaunch red & the Adilia Proto "by you", both in a regular flex.
Worst so far has to be that V2, what a tree trunk it was.