I'm not sure on the MMM, but when I sent in my Mamba XL it took roughly 3 weeks or a month. On their site for repairs it says that it's 3 weeks for repairs and replacement times will vary with stock levels. (http://www.castlecreations.com/support/repairs.html)
I'm sure it will be around 3 weeks though.
I doubt that warranty or non warranty repairs makes any difference. I am pretty sure everyone sits in the line and turn around time is more dependant on stock levels more than anything else.Three weeks is probably about right but also factor in the shipping time as well.