I have a Stock GSR. deciding whether to get a
Skunk2 manifold or Blox. Also Blox or Skunk2 TB?
planning to get Hytech Replicas and full 2.5 piping.

 

Unless you're changing cams, stick with stock.

 

I went S2 intake -well im still in the install process- the blox manifold left quality issues unanswered from mis-aligned runners to thin casting walls, now i did not own the blox but hearing these issues made the price difference seem justifiable.
Look for a package deal s2 intake and tb.

BTW im running CTR in and GSR ex cams 11.6:1 comp

 

I've got the S2 on an otherwise stock GSR. This manifold + Exedy 9.5lb flywheel really woke the engine up. Never dynoed it, but the response is better and it feels more lively. Flywheel is certainly part of it, but the manifold helps too. Looking at headers next, maybe test pipe and then just leave it alone.

 

cool . soon or later i was gonna get s2 pro 1 cams and full s2 valve train. but will i notice a difference with IM, TB, Hytech rep, and full exhaust?

 

I had the skunk2 manifold on my stock gsr motor with ITR tb and basic bolt-ons un-tuned. The car lost a lot of low end power so I suggest you to tune your car if you replace the manifold... tune on crome If you're on a budget.

 

^
exactly - what he said, you need to tune to get best results with a manifold change.
I gained 50hp after tuning - although thats prob the result of some pre-existing cam settings.