B&M is the standard. What you want depends on your needs. the shift improver kit is entry level and costs about $30. It can be installed in about an hour. Next up is the transpak for about $50. It might take the same or a little more time to install. The installation can be done by anyone with a set of hand tools.
A couple of cautions: use jack stands!, be very careful when messing with the valve body not to let the check balls drop out ( they're very hard to find out where they go back). You won't need much more than a ratchet, extension,socket, and drill. The ones I have done came with detailed instructions. If it doesn't come with a new filter, buy one and replace it at the same time. If money allows, it is also a good time to go with an aftermarket aluminum pan w/built in drain plug.