TAR, nothing to shout about, just another training ground with lots of trainees. Not much big stuffs but the reefs is recovering and I hate the fish bombing out there as it sound so near. Further out, it is possible to run into eagle rays and whale sharks but seasonal. If you are good in buoyancy control, they will bring you to some beautiful reefs, very nice and it feel like diving in an aquarium; I had forgotten to breathe from time to time as it was so peaceful down there, maximum depth about 25m. There is an oil rig about 3hrs travel from KK, cost RM$300 per pax, minimum 3pax, heard that it is deep with strong current and big stuffs.
You could stay in KK for diving at TAR and take a boat out daily for about RM$100 for 2 dives and the stay about RM$60 per night. I love to roam the streets at night, therefore did not stay at the island resort which of course cost more. Manukan Resort is very nice.
You got to get to Labuan if you want to dive at P.Tiga, as for P.Mantanani you could stay on the island. Not too sure about the price.