just some tips from what I learnt.
1) plan your concealed works smartly ie power point/aircon/heater provision etc in terms of location and qty. particularly, wiring looping to circuit breakers, air-con blower position determines your drainage routings etc etc etc
in short, pay extra attention to all
concealed works. any re-do will cost you more. under provisions (don't do now), after moved-in, more head-ache and costly.
2) get a reliable electrical wiring contractor, wiring looping is very important, this determines your cost, not to over-load a particular circuit.
tips > have a least 2-3 swithes at the overall living/patio room ceiling downlights. (u may not need all to be lighted in one switch, elect saving).
3) get a good kicthen hob&hood, wash basin&sanitary wares, its big head-ache if u need to replace after 2-3 years. it involves damn lots of hacking eg your granite top, false ceiling, wall tiling.
4) if u do wall extention with plaster,
MUST apply sealer coat before u do new wall painting. one coat of sealer cost more than 2 finishing coats of the emulsion paint, don't save on this, without it, your new paint will fade (become whitish, discolour) in less than 2 years. be sure that u apply sealer only after the plaster is 110% dry.
be extra careful with external weather proof paint application.
re-edited>
for setia home, pay attention to their
1) flushing cistern.
2) change immediately the brown tap that u find at every bathroom wall to stainless steel (d one near shower head. ard 5ft high from floor). this tap will get loose, rusted & broken in 2 years. affect if not bother > u will see rust water lining sipping down your wall tiles.

ya ya, just recall,
very important > ask plumber to
totally wash the roof water tank before u move in. u don't want to be showering with a dead cat floating in your tank. dont'n laugh, it did happened.

Sound terrible from your experience getting a the house from SP Setia. May I know which section of Setia Alam?