What percentage raise would you need to change jobs? (career, companies, salary)

[roadwarrior101]

I'm in a pretty good position right now, although salary/career growth at my company is very slow. For that reason, I'm considering other options. I'm current at Mgr level, but I've been approached by a few companies for Sr. Mgr level roles. I've been trying to do salary benchmarking for these roles in my industry/location, but because the roles are somewhat specialized, it is tough to get an accurate read. To that end, I do have some questions:

1. Roughly speak, what percentage salary increase can be expected when going from Mgr to Sr. Mgr level? I understand that a precise answer cannot be provided, but rough ranges would be good.
2. What percentage salary increase should I be looking at to change jobs? I'm thinking of targeting 20%. Its not like I need to get another job, and I think that is in line with the ranges for these roles in my area (I can afford to be choosy and wait, if needed).
3. Are sign-on bonuses commonplace these days, given the current economy? I am in the high-tech industry in the Silicon Valley (work in business, not IT). I know its typical for companies to hand out RSUs at the time of an offer, but how about a cash sign on as well for a Sr. Mgr role? This would be ideal, as I'd likely be foregoing my mid-year bonus payout at my current company.