I didn't have a S330 but we did have a T320 that had the same engine as the one you had in the S330. When we went from the T320 to the T770 I noticed the ease in servicing that you noticed but only a slight increase in power to the mulcher head. By slight increase I mean that the head seemed to spool up a fraction of a second faster and seemed to stall slightly less when under load. Overall it just seemed like the machine has a little more hydraulic "torque" the the T320. Unless you can get a great deal on a 770I'm not sure it would be worth the hassle to upgrade at this point for a marginal increase in power.