Renew PR (REP) or take up citizinship

[SgAus]

Present SPR studying in Aus,
Unlikely to work and contribute to singapore economy before PR (REP) due to renew in 2009, will this cause big problem?
esp. given that insufficient amount of period of residency in singapore while being a PR?

Anyone can advice~~?

==another option is to take up Citizenship, under current policy, seems must be not absent from singapore for more than 12 months in past 6 yrs,
unless "SPECIAL CASE" (official reason)

but if my doctoral study can be recognized in this case, of course I can tell ICA that my study/degree will eventually benefits Singapore blah blah blah...

Need your advice again~

Cheers

==type in a hurry, forgive typos etc.