According to this page:

http://www.jetstar.com/us/en/plannin...ht-connections

Jetstar does not interline bags with Singapore/SilkAir. If accurate, you will indeed need to pick up and recheck your bags at SIN.

I'd be worried about the 3.5 hour connection, since rechecking bags suddenly includes - immigration, waiting for bags, customs, finding your way to the SilkAir checkin stations, checking in, waiting for security, etc. That's a lot of steps.

Is there any way this itin can be done with only carryon luggage?