Dude...

you should come out meet the gang sometime so we can poison you some more.
As for your suspension, Hi/Lo means you can only play around with the spring tension (pre-load) to fiddle with the soft/hard aspect of your car (sort of). This is where a good installer comes in handy. They know how much pre-load to set on the springs to get the optimum performance out of it and if done right, even hi/lo can feel comfortable. If you don't know what pre-load is and since I'm feeling a little bored in the office let me explain :
'bodyshift' - refers to the height adjustment of the suspension without putting any load on the springs. Meaning the springs are not compressed to adjust the height of the suspension. Meaning the body of the absorber itself is moving.
'pre-load' - refers to how much compression you're applying to the springs when installing them. Depending on the spring itself, a pre-loaded spring may react faster as compared to it sitting freely without any load.
The advantages to a bodyshift is you don't sacrifice spring compression for height adjustment and you get to play around with the pre-load of the springs.
And you're seriously mistaken if you think HWL is the 'best'. It's just 'one of the brands' available in Malaysia. There's FTuned, PRS, GAB, BC Racing, AR Racing, Titan, Koni, Bilstein, Aragosta, Improve, Ohlins, etc.
Personally having tried a few brands, among the 'budget' ones I'd go for PRS, BC Racing and AR Racing (the 2 are essentially the same just different brands, PRS does custom jobs). Then if I had the budget I'd consider FTuned, Koni or Bilstein. Then if I were printing money I'd go for Ohlins.
So no HWL isn't the 'best', just one of the brands out there.
And no you don't need extra fueling. An underutilized injector will fail faster than one that's used 50-80% of the time. Besides, why bother upgrading the injectors if your pump is stock?