N/a 4efe itb exhaust diameter

[JDM_MARK]

Hi guys as some of you probably know i am putting throttle bodies on my 4efe and I'm going to try and eliminate all the restrictions to get the most out of them. So starting with the intake I have got the tt600 throttle bodies obviously  with ram filters on a custom manifold then going into the engine the cylinder head is going to get ported and polished and also uprated valve sprints eventually. Then coming out the engine I am going to make a stainless 4-2-1 manifold and then carry on with the rest of the exhaust. I am just wondering what people's opinions are on what exhaust diameter to go for on a 4efe with itbs.