Hi Naman,
I've been told that HTTP classes are an optimized implementation of the iRule logic. I wouldn't expect significant gains over a well written iRule though. Perhaps someone could give you tips here or in the Performance Testing section (
Click here).
There aren't any hard set limits on the number of HTTP classes you can use or how many entries you can have in a datagroup. It's dependent on system resources. You could try doing performance testing with a number that is much larger than what you expect to actually use.
Aaron