1996 i30

I looked at an i30 yesterday I am thinking about buying. It drove nice, but when pressing the gas pedal it made a high pitch howling noice that got louder the faster I went. It sounded like tire noise. I'm contacting the owner to get his take. Any ideas on what it could be? Thanks.

My hearing fails me... In any case, use/buy/bribe some pro source to get second opinion before paying.