What type of vent are you fitting?
I've just fitted a set of Ast*a GTE vent into my spare sapphy bonnet for my car, by cutting the astra bonnet and taking the 'hole' that the vent fits into, then, I cut the Sierra bonnet, and welded the 'hole' into it. Skim of filler, looks factory!
Most vents the tools you will need are: angle grinder, or if you are carefull, tin snips, if using snips, you need a drill aswell, and some form of sticking the vent in, silkaflex is great for this.