2)Is NewEgg trustable, because they have a REALLY good price for the HV-20
I have not heard bad things about NewEgg - they sell lots of computer gear.
3)Which boom Mic do you guys recommend?
I presume you mean a shotgun mic mounted to a boom - how much do you have to spend? In my opinion, best is Sennheiser... You will also need an XLR adapter like http://beachtek.com/dxa6vu.html
Beachtek recommends the DXA-2s for the HV20, but the phantom power available in the DXA-6a and 6vu will be really helpful with the higher-end mics than can use phantom power.
Audio-Technica makes good shotgun mics, too...
For you to think about: Is stereo required or mono acceptable?
Maybe this helps... http://www.lafcpug.org/review_shotgun_mic.html
In addition to the boom (your boom-ops person would really appreciate a nice graphite or aluminum or carbon fiber boom pole/extension like those from http://www.coffeysound.com/home.php?cat=5 ), a shockmount (either from the mic manufacturer or a Sabra SMM-1 universal shockmount is suggested) and if you might be in a windy (outside or even near an air conditioning vent), a zeppelin (also referred to as a "dead cat") will be required. You can make one <http://www.joelandkaren.com/mic-zeppelin/> or buy one from folks like http://www.rycote.com/