hello m8, u got to ask ur self wat u lookin for from ur system. if u want crisp clear loud then u want to spend a lot of money. but if ur like me u want something thats is quite loud clear enough to hear but dont have a lot of cash, then u will be ok with std speakers, as long as u run the stereo flat.
sub... u want crisp and clear 10", slightly deeper and less clear then 12" and if u want a mega bass line would go for a 15". then u got compertition subs, eg, 12" with bigger bass line than a 15" and clearer than a 10".
amps. well depend wat u want to run. if u r sort on cash but u want a loud system i would go for 6x9's running off an amp, u will need an amp for ur sub so u could end up with a) 2 amps 1 for sub and 1 for speakers. or b) 1 good amp with channels to do both.
Speakers. i got JBL 5x7's in the front, JBL 13cm in the back,JBL 6x9's going in to my boot with my boot build, i got crisp clear noise but i run my stereo flat.
Smee