Best set up for ct 20, how do you secure down pipe if you dont use the original bracket?? any other info would be good, muffler suggestions etc.

 

For a turbo, the best exhaust setup is the least resistant exhaust setup.
As you've got a CT20, match the diameter of the outlet of that turbo to the diameter of the pipe you use.

I'd suggest that you don't secure the turbo to the engine/transmission, instead, use a piece of flex tube, close to the downpipe. This helps to keep the ct20 housing from cracking (and racking up $$$ repair bills)

This is the sort of thing I'm talking about:




For a muffler, a simple, low cost, low restriction muffler works great. You can go nuts with flowmaster or any design you want - but typically generic "turbo" mufflers work just fine.