Definatly the B18c if your planning on boostin it down the road. You'll gain more performance. as far as what to expect, if it's a full swap, you should have everything u need parts wise.

All thats left is to make sure you have all the proper toolz to complete the project. If you haven't done it before & know someone that has, it's nice to have them handy, maybe they can be around for help & moral support

good luck with your project!