Is the new gasket supplied in the new filter kit good enough to use or does anyone recommend anything else, like reusing old rubber one from factory?

 

Reuse the factory gasket, you'll be fine, the flimsy rubber & cork ones suck...just torque it to proper spec, my 46re was 13 ft. lbs. If you've had it off several times before, it might be wise to buy a new o.e. gasket, they're only reuseable a few times.