Don't worry about loud, my 6.5" factory speakers were 'loud'
don't jump on the deal cause it's cheap, there's deals on here in the classifieds all the time, and there's deals 24hrs. a day on
ebay.
Find out what kind of sound you're going for, there's so many variables when you say 'loud'
Do you mean loud for personal use? Loud for DBdrag? Loud for Street Beats? Loud OUTSIDE the car, to be an *******?
The sound you get depends on box type, box size, box tuning, speaker size, car, dampings materials used, the amplifier, crossover settings, the setup of the other drivers in the car.
They'll both be loud, that's what they're meant to do, even when people talk about relatively low output from a sealed enclosure, it's all relative if you have good equipment.
And lasty, before you snag some sweet deals on 800 subwoofers, make sure you can afford REAL power, and electrical system upgrades to power the amp.
Cause either of those setups are going to **** with a 8,000,000 boss amp that puts out 43.8w rms, or an orion2500d that's hooked up to a 60A alternator, and 8 gauge cabling.