I happen to be in Chennai a lot and have never really thought of driving down. But recently found myself with the urge to explore Indian highways (only civilzation point A -> B for now, thank you very much) and got into my car at 5 am.
360 kms in ~3.5 hours. The drive upto Chennai was great with clean, comfortable 2 lane highways. However, the Mumbai-Pune expressway is still a league apart.