need advice on what stereo to get

want a single 10 or 12 in a box

new speakers all round (staying 5 1/4 so they are hidden)

and amp to power the sub and one for the 4 speakers.

budget approx 500 quid, and a i already have a headunit.

this is all going in my saff 4x4 and i would like it to be loud, if possible.

my friend has a single 10 in his car, and it sounds awesome (mtx thunder, with cheap amp)

cheers for the advice guys

rory