M6TVV

ok newbie and non mechanical person, i have today been offered a w reg impreza sport, but a previous owner has took the air filter completely away and as a result there are now 3 small filter's attached to small pipes one to the left one to the right and one to the middle of the engine, where i'm guessing these would all feed into the standard filter now my Q is,is this the right thing to do and will it damage the engine??, also the clutch engages quite high is this normal? Finally you'll be glad to know is how much is a belt change roughly so i know if the garage is taking the p when i ring then for a quote,
are there any common faults to look at please its a w jan 2000 2.0 sport standard apart from the above air filter removal.
Please help as i need to give an answer tonight to the seller
Rgds
Mat (m6 tvv)