there's 2 ways you can go....just use an existing hole for one of the sicce pumps and then cover the other one (there are caps),
or drill a new, larger hole in the skimmer body and bubble plate to accomodate the larger askoll pump.
I think if you use the existing sicce hole, you are limited to getting like -65-75 scfh, as opposed to the 90scfh that pump getsz unrestricted....
but either way you slice it, yes, it's a huge improvement over the sicce pumps, no start up issues, less noise, more power.