I'm on MegaMek 45.3, and I get pretty much the same as Sabelkatten if both SL are now gone - bar the BATA weighing an extra 100kg; errata somewhere?
So you've got another 140-240kg to play with, and 2 more crits without any turret shenanigans, or consolidating your ammo (which seems to go up to 8 shots in one crit).
Presuming only 140kg, you could;
-Bump armour to 8 and be able to tank a LL, add 2 extra rounds ammo, and take 2 APWM for token AI and maybe smoke grenades
-Increase speed and ammo each by a third (+1/+4)
-Add 4 ammo, an LMG and APWM
-Add 6 ammo and a Firedrake