I'm switching out the side mount IC that I have, the pipes that come out of it are waay too small, like under 2". It's an eclipse side mount.
I want to switch to a front mount for the bigger piping. If I make this switch, do I need to re-tune?

 

I don't think that you would, but just remember that bigger pipes = more turbo lag. I don't know anything about your setup though, so this may be a null issue.

 

If you're flowing more air, you may need to re-tune, but drive it first, if it acts funny, then you have your answer. Just be cautious, don't push a turbo engine too hard if it does something you aren't used to unless you know the specific condition causing the activity and know it won't cause harm.

 

larger i/c also means more pressure drop between the compressor housing and the manifold...