i'm just a newbie but i hope i can help clear some doubts.
SQ= Sound Quality. You wanna be able to hear crystal clear sound. The speakers should be able to project out the true blue vocals by the singer with proper sound staging. Typical SQ music are jazz, guitar, r&b.
SPL=Sound Pressure Level. Mostly associated with hip hop and techno. You wanna let your frens know you're reaching his house and this is the perfect way of telling him from 1 km away. All about earth shattering bass and lots of sub in your boot.Typical SPL music are pasar malam fengtau remix, dj tiesto, paul van dyke, any rapper music.
the CX,
mohawk products are considered the cheaper brand among enthusiast. i mean i'm not saying its lousy but its for people with smaller budget to play with but then don't underestimate its capabilities. though its cheap, it'll easily match a more expensive brand in terms of SPL. lets just say...you buy a RM8000 tag heuer watch and A RM 3000 citizen watch. both can show you the time perfectly fine but its the R&D that goes behind it, the quality of the parts they use, the craftmanship and to some extent the brand name. if not mistaken, the orange is the highest range followed by red and blue.
for a decent SQ setup, you'll need at least a reputable 2 channel amp. 1 channel to power the front component and another channel to power the sub. for your rear speakers, you might wanna use your pioneer HU to power it up. however you might wanna make do without your rear speaker coz from my experience, rear sound will distort your staging slightly. for a basic SQ setup without HU as i mention above, i think RM 2000 should be ok. it sounds a lot for a beginner, but to produce nice SQ, i truly believe you need a slightly better amp, not those china, taiwan ones which can amplify loud but not clearly. i think its fair to splash RM1000 on a amp and balance out RM1000 on components and subs with installation.
quite rightly said, do not make rash buys in cheap products. i'd rather save up to buy a slightly better and branded product than to buy a cheapo product that will give way after 6 months or so.