Nope. Market value for both of those markers used is about the same, usually a little higher for the etek 3. Don't add $150 unless it comes with serious extras you need like an in hydro tank, FULL barrel kit.....whatever.
If you really want a protege sell your etek 3 and buy one, save some cash. If you find the right buyer or have enough upgrades you'll be able to afford a Vice, give or take $50.