The Alpine range are good and reliable, as are the slightly cheaper Focal's, JBL ect. As for an amp get a small 2 channel amp, JBL do some good value ones. As far as mounting positions possibly under thedash/in the dash somewhere, wait untill you get the amp or do some very precise measuring, start by taking the passenger side bottom cubby hole/glovebox off have a poke around. Or if you have a3 door, in te rear quarter panels theres a fair amount of space.
Get yourself over to Talkaudio forums, and have a browse on caraudiodirect aswell theres lots to learn from some of the top guys in the country for installations