I've lost .01 on my audio reaction time in the past six years. When I attended Brownie's class, I was at .13 consistently. Now, I'm .14. It's great to be able to quantify such details.
Dry fire with effective technique should more than make up for loss of reaction speed. At least it has for me.
I cut a 1.42 from concealment today on a 25-yard A-zone shot, and was consistently 1.5-1.6 on a full mag through the Glock 17. Two months ago, when I became serious about it, low twos were as good as I could muster. Dry fire every day, live fire every day or two, and here I am, nearly where I want to be with it.
Brownie has been one of my inspirations in my pursuit of better. He gave me great tools to start out with.