What is the difference between ADS2003A and ADS2003C?

Is there anyone who is kind enough to explain the difference between those two programs?
I tried to find out on the website but failed to get an answer.
Looking forward to getting answer from somebody who knows the difference.
Thank you.

1)Provides accurate nonlinear simulation performance. Unlike existing models for GaAs which are based on silicon models, the AgilentHBT model is accurate for large-signal modeling of III-V processes like GaAs & InP.
2)Faster Data Display and improved Data Display synchronization with the simulator greatly improves tuning interactivity.
3)Microwave mode now has MomentumRF technologies like arbitrary polygonal mesh (mesh reduction) and DC/low frequency stability. These provide smaller problem size for faster simulations, greater capacity, greater accuracy & dynamic range and improved low-frequency performance.

These, and other enhancements, provide:
~20% less memory used, enabling analysis of larger designs, and
~15% faster simulations
4)Harmonic Balance Speed has increased: 1.15x faster on HP, 1.33x on Windows, & 1.50x on Sun.
Many of the improvements for HB also benefit other simulators like Circuit Envelope, Transient, etc.
5)Faster MATLAB co-simulation with Ptolemy Increase performance of Matlab Cosimulation by 50x.
New Symbolic Defined Components, similar to SDDs in the A/RF environment allow for easy creation of custom components:
6)WLAN, TD-SCDMA & 3GPP WCDMADesign Library Improvements
7)New Ultra Wideband DesignGuide

Hope it helps ~

I think there is also improved interface to C/A/D/A/D/C/E throught R/F/D/E

You can find ads2003c highlight Note.
http://eesof.tm.agilent.com/products/ads2003c.html