relocate to Singapore : different types of PR??

[kn1ghtx]

Hi,

I'm married to a Singapore Permanent Resident (SPR). right now, I'm in Canada and my wife is in Singapore. I'm planning to move to Singapore, but obviously I need a career there too.

a little info about myself:
I graduated from a Canadian university and have been working as an Electrical / ASIC engineer since 2001.

I understand that a spouse of an SPR is eligible to apply for SPR as well.

I have some questions about SPR application since I couldn't find the answers from ICA:
1. is it true that the spousal SPR thing only works if the husband is the SPR holder? or t works both ways (wife can sponsor husband for SPR as well)??
2. are there different types of PR when it comes to spousal sponsorship? I heard from word of mouth that some type of PRs obtained by spousal sponsorship are restricted (eg. not allowed to work in SG)??
3. if #2 is true, what's the strategic way to help me move to SG (status wise)?
4. what is In-Principle PR?

Thank you very much for the help...