See question BELOW:

The plan:
I'm planning to build another turbo setup (total DIY) kit for my CRX with b16 motor. I know there are cheap kits out with almost everything for around $500 but I can do even better than that. My new (to me) CRX is my daily driver (only about 15-20 miles a day), but I'm building it for quick spool for some fun driving. This rex has AC and I am absolutely going to keep the AC, no questions asked (so don't ask). I'm also going with a TD05 16g turbo because it is more than adequate for what I'm after (about 210-230whp), and fits better than the larger T3/T4. I'm doing the half radiator with slim fan and a custom log manifold. Yes, I said LOG. I'm welding my own stuff, etc.. etc.. but that leads me to my question:

QUESTION:
because I'm going with a custom log manifold, what's a good diameter for the "runner's" 1", 1.25", 1.5"? I had someone tell me 1.5" but that seems too large for each runner...

Few pics of the REX:

 

I'd make the runners the size of the exhaust ports and the "log" part itself about double the area (not the diameter).