I don't think that I've EVER found a petrol station in Ireland that DIDN'T sell diesel.  The other advantage (beyond the $20 price difference) is that the diesel will doubtless get better fuel economy, 'though the price of fuel WILL be a tad higher.

We drove a diesel Passat over 2500 kilometers in Ireland last summer.  This year, we are opting to 'downsize to a Corolla (or equivilent).  The Micra is a nice, little car, vaguely reminiscent of a VW bug.  If a two door doesn't disturb you then I'ld say go for it.  It's a comfortable enough car for two. 

As far as road 'room', I dunno if there is any SIGNIFICANT difference, though.  I've driven everything from a small, 2-door hatchbacked Alfa Romeo, all the way up to a 9 Passenger, Mercedes Vito, diesel van and numerous models in betwixt and between.  The only truely desperate moments were with the vans.

Here's a link to a previous thread on the topic:
http://ireland.activeboard.com/index.spark?forumID=65127&p=3&topicID=17605776

Hope this helps(?).

Bob

Hi Michele,

I have been trying to email you about mapping for my itinerary you did for me.  It hasn't bounced back and I hate to keep bothering you but are you still able to do it.  Thanks again,   Stephanie Gaglia
P.S.  I can't believe it's only 3 weeks away!