I was thinking about putting three 10" subs in my '91 Vette, so I posted an earlier thread asking for suggestions and a few people suggested that I run just one 12" sub instead. Personally, I think three 10's would fit nicely, sound better and get louder than just one 12, but I'd like to know what everyone else thinks about it. The maximum dimentions I have to work with are 34" x 12 1/2" x 18". Thanks for any input.

Size of cone does not have much of anything to do with how good it sounds. Honestly, with a good install and quality equipment, you can run smaller and less drivers then you think. Heck, maybe just start with a pair of 10's in a well built sealed box, run them clean unclipped power and go from there. Keep in mind, you will have the sub inside the cabin with you, so you will have more perceived output then you might think.

I think 10's would be better for you

3 tens in the same size enclosure with same power will have more output.

Assuming that the box is the right size, the 10s have the potential to have less distortion at a given output compared to the single 12. The reason is that they have a fairly substantial advantage in cone area and thus the subs would not have to move as far to get the same level of output compared to the single 12. Additionally they would suffer less from power compression because the power is divided among 3 coils instead of all going to one.