Here is my analysis, non-scientific.

With the shaft (KBS Tour-90 + grip + length) the exact same on either club heads:

#6 iron weight
2014 TM Tour Preferred CB: 265.3 g
2015 Titleist 716 AP1: 261.8 g

Difference: 3.5g

Therefore:
From your current #6 TM iron, if you put the same shaft and grip onto a #6 Titleist 716 AP1, your swing weight will decrease by 1.75 swing weights.

If your current swing weight is currently D2, you will be looking at D0 and a bit.

So your saying if I add the kbs tour shaft (the one I have in my tm irons) to the ap1, then my swing weight will go from a d2 to a d0? Sorry I don't really get these swing weights.

hard to say without some grips, ferrules and epoxy. i'm in the same boat with Modus3 105x shafts but taking them to my local club maker to make sure mine are all D3 as that's what i prefer. any good local club fitter should be able to dial them in for you to your specs.

I would get fit from a Certified Titleist Fitter. Not only will they answer that question but you can feel the difference during your fitting. They will fit you for you with regards to head, shaft, grip and swingweight!

Hi Michael,

Assuming standard length, grip, and grip size the KBS Tour would build to D1, and the KBS Tour 90 to C9.

Hope this helps