You are right, Mr. Slim is now being assembled in Pakistan while heavy industries model is manufactured in Thailand. I also have the locally assembled Mr. Slim in my home and and it is also very good. It is difficult to compare the two because they are installed in very different places and one model is 1 ton while the other is 1.5. However you could say both are equally good.
Installation kit includes high and low pressure pipes, separate foam insulation for both, AC bracket, 4 wall mounting bolts for AC bracket and 4 nut bolts for securing outdoor to the AC bracket. Prices are given in the first post.
It is very rare to get a gas leakage problem in a new unit due to a manufacturing defect. Gas leakage is mostly because the installer did not properly check for leaks while installing the AC. Finding the right installer is difficult. Ask around and pick the installer who has a vacuum pump.
Mitsubishi Heavy Industries AC is imported by Aura Electronics ask around and you'll find their address. Mitsubishi Mr. Slim is assembled in Pak by Orient Group, their office is on Chamberlain Road.