You're being the turd in a punch bowl here, LEO. Coming off as a complete dick.
How many times have we read the "experts" say that if you're going to post a question give as much info as possible. I agree and there should be a template. Cubic inches, Cam, convertor, gearing, tire height, .......
The info can be tailored to the specific question but putting more info that necessary might not hurt.
I, in no way, shape, or form got that his post sounds like an advertisement. I think a cam would be one of the factors on header purchase. Do you think a 224/224 duration cam warrants the extra expense of 1-7/8" headers? I don't. But can't trust me, I didn't work in the automotive industry for 40 years and I'm not as old as you are.
To the OP, sorry you got "the business" from a member of "the mean girls club" on here. Thank you for providing the cam specs. After talking with Brian at IMM and doing a ton of reading on my own, with your cam specs and the use of TF 190's, I would definitely go with 1-7/8" headers. 2" headers would be wasting money and adding more of a fitment headache with your head and cam combo.
The TTi step header is more of a replacement header, ie. replacing manifolds. If you are building an engine for serious performance like you are then my expert tells me 1-7/8" all the way. IMM has dynoed a lot of engines and they use 1-7/8'' and recommend them. So, don't trust me. I'm just an enthusiast. I think there is enough consensus here saying go 1-7/8".