this is a common mod. lots of people replace the standard filter with a k&n or similar panel filter as well. the standard airbox is actually very good on the coupe so there's no need to go for a cone filter (unless you wanted to)
if you dont want to mash your existing airbox drilled ones come up for sale for a couple of quid (literally) in the for sale section from time to time
the previous owner did my airbox (no longer have as i have a different turbo & Straight induction pipe) but the holes were on the side rather than underneath.
hope this answers your question!