Should I replace my encoders??

Hello,
I just acquired 3 SEM 30lb DC brush servos to replace the steppers on
my Series 2 Bridgeport. The servos have Heidenhein ERO 115 encoders
installed and from what I've read they are 125 line. So I guess my
question is should I replace them with a higher resolution encoder or
will they be OK. The servos are 2500 RPM and there is a 2 to 1 belt
reduction to the ballscrew. I haven't decided on a controller yet but
I'm leaning towards MACH and Rutex. If I do need to change them how
much trouble is it going to be and do I have to do some kind of phase
alignment? Any help would be much appreciated.

larry@...