Buy new irons or no?

I am a 10 handicap playing with Mizuno MX-300s I bought in 2009/2010 when I was probably a 14.  I know I had a basic fitting but nothing like the one I just got.

The pro I worked with suggested Titleist AP2s with a custom X-stiff shaft and a few other modifications because of my swing speed.  Trying to figure out how much I am going to get out of the switch.  The thought is that my Mizunos are spraying left and right because I don't have a stiff enough shaft (no jokes allowed on that comment).  Also the AP2s might perform better as I am playing more and pushing to get into single digits.

You need to test the different shafts on a driving range (grass) and repeat the procedure a week later or so  just to make sure you are spending +1000 usd correctly. If you could spend $ 50 extra  for a trakman session outdoor would be perfect.

Thanks.  I did spend an hour off grass, mat and he was using the Trakman the whole time.  I am not buying the clubs from him so he has nothing to gain.  Suggestion was around the feel of the club, swing speed which warranted an x-stiff shaft and I flight the ball high which seemed to be minimized with the AP2s.

Does the added stiffness help you more with the longer irons or the mid irons? What is your left/right dispersion before and after the change with your different irons?

I have the 710 model and changed the shaft from S300 to XP95 (around 100 gr) and I was surprised while testing that I wasn't losing distance and dispersion was similar. The reason I changed was due to fatigue on my elbows tendons.

Anyway you have to test your 4 and 5 iron as well because those with an X stiff shaft require high maintenance, so to speak.   I never doubted on your friend/coach suggestion, I m just saying make sure you are 100 % sure what you are getting .

AP2 is a great choice imo. Ask Titty to check the swingweight of the set because I had to add some lead tape (2.5 swing weight difference)