Exporting Audio Files for mixing

[uptowners2010]

ok i use pro tools 8 le and i use virtual instruments. now i know about recording audio and that you have to record it at the highest level before distortion, but im using virtual instruments, so if i wanted to export strings to mix in another program or a mixing engineer, would i have to set the level to the highest before it hits distortion and then export it,,or it wouldnt matter because it was recorded internally via virtual instrument. i guess the question im really asking is, how do i prepare a song for mixing later on. like levels of each track and such ?