I just picked up a set of 3 sunpros off of Ebay.
If you buy them new they should come with all of the hardware to bolt up, especially since small blocks are one of the most widely made engines ever (I presume you have a smally).
Either way, everything should screw right in. If you buy it new, all the sending units and lines come with. If for some reason a sending unit wont screw into your engine, for instance the temp sending units threads are too small/big, summit racing carries all the adapters you could need for this.
Hardest parts routing the lines through the firewall and hooking up the backlights