that site is bullshitting you, the 10" ones are only 1000w. and i'm almost positive that's peak. they'll hit but they won't hit THAT hard. i didn't even realize you were UK, no idea what any good subwoofer sites are for there.
as for head units, kenwood or pioneer. personally i'd pick kenwood. i snagged a cheap pioneer one and i've had a few problems with it shorting, but it's nig rigged right now hahaha.
you said "loud and deep." 10" can be louder than 12" subs but generally they won't be deeper. stick to well known companies. i've never even heard of t1 or whatever.
Polk, JL, Audiobahn, Rockford Fosgate, Pioneer, Kenwood, MTX, Kicker, and Alpine are all well known and popular. The rest on that site are like ehhhh.
generally get an amp that will supply 500w+ MORE than the combined RMS of your subs, and just tune it down a little. Menace is a really popular amp brand. The 3000w amp is sooo good.
Avoid Sony. They suck. End of story.
@Bennett you'll need an amp, even if you only get speakers and no sub.