Sukkykoku

I buy 20 speakers from "Pioneer" and wnat install in my Yaris YR-X. However my mechanic sayd only 10 can fit! Wrong I think... Three on each door (6), two in each a-pillar (4), 10 in rear parcel shelving (10), so easy 20! Is there legal restrriction?

oh wo yeah! sounds heaps fun! my best friend from japan arrives in Sydney on 25 December so yeah!