normally a condo next to an HDB within the same location is about X 2 in quantum, you see 91sqm (aout 1000sqft) Punggol flat is > 500k already ... so if you price less than 2X ... people will snatch like no tomorrow
294 Punggol Ctrl 16 to 20 110.00
Premium Apartment 2003 $595,000.00 May 2012
161B Punggol Ctrl 16 to 20 114.00
Premium Apartment 2004 $585,000.00 Jul 2012
293 Punggol Ctrl 16 to 20 91.00
Premium Apartment 2003 $512,000.00 Jul 2012
632B Punggol Dr 16 to 20 91.00
Premium Apartment 2007 $553,999.00 Jul 2012
and from prediction HDB resale flat has 25% more to go b4 peaking ... that is to say 91sqm Punggol Central HDB will be > 600k in a few years time
Ride at your own risk !!!