RH12 >> the 30 and especially the 32 get heavier loadings than the 20 (even though that regularly has a full bus for small parts of the route)
The 020 is one of those routes that carry relatively few full-route passengers (anywhere between Galway/Oranmore and Maynooth/Dublin) and rather is a cross-country commuter route, carrying people to and from Galway, Athlone and Dublin instead. The X20 on the other hand is the main Dublin/D-Airport - Galway express route for Bus Eireann (although, as I already mentioned quite the number of times on this forum, the lack of night services makes it rather useless for a considerable number of flights from Dublin) which, nevertheless, was already scheduled for some downfalls (unrealistic schedule and the hoppa-hop to Loughrea and Ballinasloe - who's bright idea was that?!), considering that it's bihourly and there's already Citylink and Gobus with mostly hourly frequencies throughout the day...
In other words, I believe that the most the 020/X20 combo should get is an SE, no more. Doesn't suffice? Get an SP out there, more legroom.

Oh, btw, I'm back from Poland :) Gotta get uploading to Flickr... :D

[personal opinion]Irish Rail need to introduce train numbers... to the public![/personal opinion]