Yaris 06 T Spirit advice needed !

[nocturne_sa]

Howy folks!

firstly, I'm a new member so a big hello to all. I was wondering if you guys could offer me some advice.

I am interested in a certain Yaris 06 1.3 T Spirit 5 dr auto. It's got 12K miles on the clock with full service history, very good condition etc and is being offered to me for £6,300. I'm trying to bring it down to £6K but I don't think its going to happen. So I have a few questions:

1) Is this a reasonable price?
2) My journeys will involve motorway travel (around 10K miles per year total) so should I be looking at a 1.4 diesel? They seem to be around 1-2K more expensive. I assume diesels will require more maintenance?
3) Are they reliable?
4) How is the semi auto gear box?
5) Are they comfortable for long distance journeys?
6) is it possible to fit after market (prefer original Toyota) parking sensors?

Any advice will be much appreciated. Thanks!