Garage door torsion springs are not scary at all. I've wound them up with a pair of 12" ratchet extensions; that's plenty of leverage. It's all FUD from the door industry trying to preserve their margins. For some reason it's too dangerous to install your own garage door spring (which is contained by the roller bar it acts on), but you can borrow an automotive spring compressor for free from any McParts store. The auto spring is an order of magnitude more potential energy.