The IRS DOES do random audits each year
And I know it's a lot of trouble, but it might be more efficient to go there (keeping control of your paperwork, rather than sending copies off in the mail) and getting it over and done with in one meeting
Here are your rights, as a taxpayer:
The IRS trains its employees to explain and protect taxpayers’ rights throughout their contacts with taxpayers. These rights include:
Also see this:
An examination may be conducted by mail or through an in-person interview and review of the taxpayer's records. The interview may be at an IRS office (office audit) or at the taxpayer's home, place of business, or accountant's office (field audit). Taxpayers may make audio recordings of interviews, provided they give the IRS advance notice. If the time, place, or method that the IRS schedules is not convenient, the taxpayer may request a change, including a change to another IRS office if the taxpayer has moved or business records are there.
The audit notification letter tells which records will be needed. Taxpayers may act on their own behalf or have someone represent or accompany them. If the taxpayer is not present, the representative must have proper written authorization. The auditor will explain the reason for any proposed changes. Most taxpayers agree to the changes and the audits end at that level.
Here's an article from intuit regarding random audits - Dated, but might be helpful: http://blog.turbotax.intuit.com/2007/06/15/the-irs-random-audits-are-back/
Finally, here's what the IRS says about audits: http://www.irs.gov/uac/The-Examination-(Audit)-Process
But again, to answer your question; If it were me I think I'd rather set it up, go there, and get it over with. (You MAY, when you call back, want to put them on notice that you know about their PUBLISHED "right to know why the IRS is asking for information, how the IRS will use it and what will happen if the requested information is not provided."
I hope this has been helpful ... The links provided here will stay active; Feel free to bookmark and come back for future reference
Let me know if you have questions