pecan2phat: If your lights are safely out of the reach of any splash,by all means remove the guard. If not,you may want to consider a glass cover(non-UV filtering). Yes that happend to me as well with the warping,but it wasnt the shield...it was my tank!!
keeperofthesea:1.Yes,good quality kit(at an exceptional price!)
2.Yes , 4 will be enough for lower light tolerant SPS as long as theyre kept along the upper 1/3 of the tank,montipora sp.,some pocillopora sp.,psammacora to name a few.Generally speaking greens are lower light, as opposed to pinks and purples(higher light).3.If you wanted to expand your sps potential,Id recommend a 6 bulb combo.4.Yes having a canopy would make installation much easier for your retro kit as it wont have any legs or hanging device to come with it. MDF(medium density fiber-board) can be used for a cheap alternative.HTH.
-Justin