Years ago I was recording in a studio, the other guitarist had a hard time with a section of a lead, so the engineer slowed down the recording, the guitarist tracked his part, then the engineer returned the song to the original tempo. There were no pitch issues, to timing issues or artifacts that we could hear. He said he learned the trick from one of the engineers on the most recent (at that time) Dragon Force album.

Is there a way to do that in Sonar? I am doing pre-production on a project and I am having some trouble with a lead part I am working on. I've gotten to where I can play it at about 85-90% of the tempo and feel confident I will be able to have it right by the time it gets recorded for real, but to not hold up the pre-production and to hear these licks in context I would like to try this "trick". If this is possible I have a few concerns, the drums in this pre-production project are SD3 so I know slowing down the tempo is just a matter of changing it but what about for the recorded instruments? And once I get back to the original tempo how will the lead part I recorded at the slower tempo sound?

1. Do a premix of the existing tracks starting from the beginning of the project. Snap the end to a measure boundary.
2. While holding Ctrl+Shift, drag the premix longer so that it's the desired duration. Mute all other tracks.
3. Select the premix and bounce the clip to itself to improve fidelity.
4. Record your part. After recording the part, if necessary, slip-edit the beginning of the clip to the start of the song.
5. While holding Ctrl+Shift, drag the part you recorded shorter so its end snaps to the measure boundary defined in step 1. Bounce the clip to itself to improve fidelity.
6. Delete the premix.

 
 
 

I was gonna look up, and post the link to Craig's tip 

I have done this but by using a control on the RME Fireface that I can change from 24/96 or 24/44.1 etc  faster or slower by up to 4 % .  I have slowed down, recorded vocals that could not be reached,
then move back to standard with no real artifacts. I am sure not all interfaces can do this.  I will have to try Craig's method next time needed. 

stm113cw
Is there a way to do that in Sonar? 

 Good Day, Craig has summarized this (and humbly as well, LOL.)  So I'll do the plug, check out Craig's, The Big Book of Sonar Tips, Chapter 12 for a couple of scenarios you may want to try, and lots of great other tips well worth the small cost.
 
 
http://store.cakewalk.com/store/cakewalk/en_US/pd/productID.5111689600
 
Cheers