Seems pretty good.
It really depends on the discount given by your common friend since getting it brand new would also mean warranty support from the manufacturer. On the positive side, you're assured that the subwoofer is done or half-way in its break-in period
Some points:
1. The Cadence really seems to be the go-to-separates for LnC at that price point. So wala tayo questions dyan.
2. If you plan on pursuing car audio further, I would suggest the RE XT800.4 for its four channel flexibility. Just in case you are going for raw drivers in the future. Then again, it (RE XT1600.2) might also be a good choice since you can always throw in another amplifier if you plan on upgrading and this can be positioned to power the midbass.
Most people I know pursuing LnC eventually go with 15-inchers. Why 15 inches? For bass, you need to move air. Increasing the cone area = more air displaced = BOOM BOOM!'
Kakayanin ba ng single battery?
What's your car pare? Most modern cars wouldn't have difficulty driving those. Remember that the primary source of power when the engine is ON is the alternator. It will only draw power from the battery on scenarios wherein the alternator needs help. As my rule of thumb, I wouldn't worry about it unless your lights are flickering during bass notes. And if it does, don't go for the product below but go for a Big Three Upgrade. In fact, I would wholly recommend a Big Three upgrade as a MUST in any car.
Lagyan na lang ng capacitor?
A capacitor is not a battery. In fact, a car battery is several thousands more powerful than a capacitor. For those who are already enlightened enough to do research knows that a
capacitor is primarily a marketing gimmick. Still, most people don't know that and it definitely looks cool being showcased beside your amplifiers. A branded capacitor would cost you 5,000php upwards. For that kind of money, I'll get myself an additional battery -- Stinger SPV20.
Marbel (distributor of RE Audio) recently unveiled the newest XTX lineup just this week. Might be worth a quick look if you're in the market for some brand-new amplifiers. As with most car audio manufacturers, these are Class D-E amplifiers so they're very efficient.