The harness plug for the switch is on the gts dash harness, im not sure if the sr5 dash harness has that built in or not. You can always follow the electrical manual and run your own wires though.

Just in case if you go with the toyota coils (1zz/1nz) you can get a set of the plugs to build or pigtailed from http://www.bmotorsports.com/shop/index.php/cPath/109_219 one of the "4-way Japanese COP plug" combos.

You will save a lot of time / money and headache (shop hours too) if you can find a donor gts that you can just give them to swap the stuff over. At the very least most of the stuff up to and including whats mounted on the firewall (pedals, dash harness etc etc). Rear axle and prop shaft will depend...

For reference, a timing light should work fine just by clamping on the COP harness of cylinder 1 (or any cylinder really), without the need for hooking up a spark plug cable in between. Also for the cam angle sensor/wheel cover I cut the 20v dizzy cover just a bit taller than the gear and epoxied a ...