Hold your horses on changing your mind that quick, i had a look on the interweb and found a web page devoted to giving advice on how to convert regiments of the guard!

it was :
http://www.librarium-online.com/forums/imperial-guard/47308-ultimate-imperial-guard-conversion-guide.html
This is the guide
The Vitrian Dragoons
These guys take a lot of work. The best way to make them would be to use Cadians as a base. 'Scrape away' the creases and folds in their fatiques to make the uniforms more form-fitting. Next, get rid of the 'coaty' bit on their legs. Get rid of the Imperial Eagle on the helmet and the shoulder pads. Now lay a thin layer of green stuff across the chest, back, forearms and shins. Build the helmet down with green stuff so that it covers the face. Let the green stuff settle for about half an hour and then carefully cut a vision slit in the helmet. Next cut diagonal lines across the green stuff layers in a criss-cross pattern so you have a pattern of diamonds.
-Colour schemes: Paint the non-diamond area in flat black. The diamond area is then painted silver with a light wash of blue ink. Weapons and helmet are black. A good effect would be to paint gloss varnish on the weapons, armour and helmet.
(Doctrines: Carapace Armour, Storm Troopers Squads, Special Weapon Squads, Heavy Weapon Platoons, Die Hards)
If your gonna do them it looks like alot of work but hopefully this is of help