Very easy to do for both of your questions. Get Raid-on-tweaker by Humus version 4.7:
<A HREF="http://hem.passagen.se/emiper/Radeon.html" target="_new">http://hem.passagen.se/emiper/Radeon.html</A>
Overclocking is easy and can be done inside of ATIs taskbar icon with this program. Activing hyperZ is just a click in Raid-On-Tweaker. Just remember to do one thing at a time to verify effects from any change. Also write it down so you can recover to previous configuration if it doesn't work out for you. Download the above program and get a feel for it and overclock in small increments. Usually the LE has no problem going from default 148mhz to 180mhz without additional cooling. Many LEs are reported to be stable at 205core/205mem with a fan attached to the Radeon chip heatsink.