I just moved my MM trailstar to the rear and put a MM addix soft on the front.
Good grip (I’d like the ultra soft but not prepared to take a supergravity casing on the front.), and the rolling is a bit slower than previously with NN pacestar on the rear, but certainly not bad, about the same as the butcher/slaughter that were on the bike when I got it, but with much better grip.
I reckon the ultrasoft/supergravity carcass would slow things down a bit, and then if you go to the double ply carcass you would want to only ride steep descents.*
* When I ran Maxxis dual plys, I found actually realyl steep ascents were OK, it was anything around flat that was a problem, flow became very very pedally.