options to increase MS Excel for Windows performance

I run extensive MS Excel 2010 for Windows spreadsheets on my iMac (27-inch, Late 2012) 3.4GHz quad-core Intel Core i7, 32GB RAM, 3TB Fusion Drive on a virtual machine VMWare Fusion 7 Guest OS Windows 7 Home.  The recalculation of the spreadsheets often requires 30-40 seconds which is quite annoying. 

I am thinking of upgrading to a Mac Pro.  My questions are:

1. Are there any Mac Pro configurations available now that would be able to increase the performance on my specific tasks substantially to reduce the response time from 30-40 seconds to say 10-20 sec?
2. What is the optimal Mac Pro configuration from the cost/performance point of view that would best address my specific task requirements?

Any advise would be much appreciated.