It's a bit tricky to get S-10's loud as said above. I had a 94 single cab S-10 for my very first vehicle. Unfortunately, I couldnt get it as loud as I wanted, because I didnt know as much about car audio as I do now. My first setup was 2 12" Sony Xplod's. I then went to one Kicker L710 in a very large ridiculous looking box with no leg room.
Then I listened to my friends' single cab S-10. That thing was insane. I thought he had a blow-thru, but he actually had two JL Audio 10W0's on a Jensen amp. I couldn't believe it. Lower level JL subs and 10's and then to top it all off, a Jensen amp. I was beyond impressed.
So my conclusion with s-10's are... They can get loud, just dont over do it. Make sure to get some subs that meet the box requirements. Too many people think that you have to go big (big magnet size, big power, etc..) in order to get loud. Not the case with S-10's.