I had read about modding the stock intake over on the Veloster Turbo forum. It seemed like someone had sized their stock airbox outlet up to 3 or 3.5".

I was about to purchase some piping to replace the stock stuff but still connect to my stock airbox so I measured the outlet. It's 4.25". While I didn't look to close at the inside of the piping it seemed fairly smooth...

So, I decided to lease the piping stock. I'm not sure what benefit there would be since the biggest aftermarket piping is 3.5". That's a pretty substantial difference.
Seems like the stock piping on the veloster might be smaller than ours.