Alternative to basecamphq project management script?

Hi there,
I was looking at the software at for managing my clients projects and it is (almost) exactly what I am looking for.

I want a similar product that I can install on MY server and make certain specific modifications to.

I have searched and searched but to no avail.
Does anyone know of a similar non-hosted version of this software? I dont mind paying.

I found ProofHub which is the best alternative because of its user friendly and money saving feature. It is a cost effective project and collaborate the things in the center so that doing work become easy and comfortable. :slight_smile: