No experience with the Microchip IP stack, I lost interest when I noted that you can't redistribute the source, for example in an open-source project. It sounds like a lot for a small uC, IP stacks this size usually implement only a small fraction of the TCP/IP protocol (eg. no fragmentation), not sure how well this will work over the internet with servers you don't control. If you ignore mandatory parts of a protocol, you risk creating a solution that only works in 95% of the cases. If it's just for hobby, this may not be an issue.