The cheaper ballast is magnetic, the other is electronic. I think the differences have already been covered in this thread. If you go with the magnetic, you should contact hellolights.com and make certain that they will light the bulbs you get, with electronic it won't be a problem. Personally I would probably go with the electronic, IMO
, they are worth the extra 50 bucks.
and what are the High Temperature wire nuts for
To wire it all up
Some of that wiring is going to have to be done close to components that get very hot, the wire nuts have to be able to stand up to the heat.