Another vote for jigsaw/reciprocating saw. Go buy one if you do much of this stuff, they come in very handy.
Use a metal cutting blade (obviously) for the sheetmetal. I don't know what to call the blade I used for cutting the plexiglass, but get one that will cut quickly, or else you'll end up heating the plexiglass and cause it to melt back together right behind the blade 😛