Just did my starmex system4 yesterday, very pleased with the results.
Guys, i highly recommend the upgraded materials. There's only 4 main materials to take note of - insulation, copper piping, drainage pipe and wires.
You don't want to be the person who finds out one year later that the wires corroded and you have to redo the whole house because the installer stinged on the quality.
Insulation: 1/2" armaflex. Cheap companies always give 3/8" option.
Copper piping: G22/G21. You'll rarely find people using G21. The smaller the number, the thicker the pipe i.e. G21 is thicker than G22. Cheap companies always use G23. G22 is usually the upgraded option. I opted for G21.
Drainage pipe: 16mm. Cheap option - 13mm. Smaller pipe gets plugged easily.
Electrical wiring: Make sure it's made in Singapore, brand like keystone. If it's china-made wires, stay away. Many online complains about corroded wires/signal lost etc.
Remember that air con installation is not supposed to be rocket science. I have read through a lot of online reviews/reports across the different local forums. I can safely say at least 80% of the issues are due to poor materials and/or installation technique.