The majority of systems we've fitted (and we've fitted a fair few now) have used Kicker KIX-404s. There are cheaper options, but to match the Empeg itself in terms of quality they're a pretty good choice. They're also a pretty powerful amp, so should more than meet your need to overcome wind noise (assuming you've got decent speakers to match).
I'm actually off work most of this week, but if you mail
sales@cambscaraudio.co.uk, one of my colleagues should be able to give you any further help or advice you might need.
Dominic
Cambridge Car Audio
http://www.cambscaraudio.co.uk