Difference between Wilson WITT mk1 and mk2

I just bought a used pair of WITT mk1 and I wonder what's the difference between mk1 and mk2
A friend of mine owned in the past WITTs mk2 and I think there's no difference between them.I think...!
Is anybody knows if the mk1 and mk2 are or arn't the same inside, internally...?
As the delighted owner of the Mk1 WITT for many years, prior to upgrading to the WP7 last year, I recall that the Mk2 had a somewhat larger diameter bass driver.

One audio writer (Colloms?) opined that the two versions were fairly close in terms of sonics.

Enjoy your new Mk1's. Although opinions differ widely, mine were splendid with ARC and Krell gear.
I have owned both. The obvious diffeence between the MKI and MKII is the finish. Not so obvious is the increase in woofer size from (if I remember correctly) 12" to 13" and a slight crossover change. The actual construction of the cabinet is also different. If you look at the bottom of the II yoiu will see that the crossover is installed with an access panel. As far as the sound, I don't remember there being much if any difference. I felt that it was a great imaging speaker that really liked to be fed a tube amp. With the right electronics they completely disappeared.

Many thanks for your help and for your advices.
My system aparts from SF Sfcd 1, SF Phono 1,
SF Line 3 and SF Power 2.
I think I'm gonna need very soon a pair of SF Power 3...
Or a Plinius 250.We'll see.
I'll think about it...