m4a volume question

Hi

I bought a track from Itunes which I wanted to use as a reference track to mix against. I noticed that it could not be imported into Cubase 5 so I converted it to an Mp3 in Itunes and then imported it to my track with its own track and stereo buss so that I can quickly solo it to comapre against the track I am mixing.

I noticed that the track I bought and imported as an MP3 clips (turns the red light on anyway - but I cannot hear any distortion). Is this common and it is ok for me to drive my track output similiarly where the track clipping light will ignite, but won’t cause any audible effects?

My main reason for asking this question is for me to try and get my track as “loud” as the from Itunes and just want to make sure that I haven’t corrupted this reference by converting it to an Mp3.

Cheers
Graham