Just in the process of doing my 30,000 km service myself. Here's the procedure I used on the air filter.
I know it's obvious, but some may need a little encouragement to have a go.
Can others check their owners manual vs. the  service passbook and see if the owners manual says change every 36 months, the service passbook saying change every 24 months. Have others had their engine air filter changed every 12 months, was the old one dirty? The cost of the new element was AU$29.95 (those in the trade must get it for less) it took a minute to replace. Is it itemised on your bill? What did they charge?

https://sites.google.com/site/instroe/i30-crdi-engine-air-filter-replacement

[2i30s]

i wonder if the crdi and petrol i30's share the same air filter.  the lower half of the air box looks like the one on my petrol i30's. 

[Surferdude]

^^^^^^^^^ .
Same air filter.

  'HYUNDAI I30'

Engine note	Year	Oil	Air	Fuel	Cabin Air
FD Turbo Dies 4 1.6L D4FB [DG]	02/08-on	R2695P	A1561	Z707	-
FD Petrol 4 1.6L G4FC [JC]	08/10-on	Z79A	A1561	Z735	-
FD Petrol 4 2.0L G4GC [JC]	09/07-on	Z79A	A1561	Z735	-
FD Turbo Dies 4 1.6L D4FB [DG]	09/07-02/08	R2655P	A1561	Z707	-

[Surferdude]

Also, if you are at all technically minded (I'm not), this page has some great info. I've read some of it and skimmed other bits.
http://www.ryco.com.au/PDF/Filters/Filters%20Technical%20Information.pdf

[2i30s]

thanks Trev.    your a wealth of information.