I was surprised to see Starke Sound SW15 reviewed by our James (I must have missed the review earlier).
I'm also very surprised to see PB1000pro (also James reviewed) beat the SW15 to the pulp in lower bass frequencies. On that, I say PB1000pro is a better choice.
It looks like you have an XTZ reseller in SG.
https://www.tritoneav.com/xtz-sound-in-balance.html
You might want to check on that. XTZ is known to deliver very good value.
I question that reseller markup, as XTZ Spirit Sub 12 is listed direct at $465(US) or about $650(SG). I'd expect additional markup for shipping/custom/reseller markup - but at $1880(SG), it seems excessive.