It will improve spool if it is not bleeding boost at 4-7-10psi like stock WG does.

Bleeding boost is the biggest killer of spool up. The turbo is making boost and the weak WG is bleeding it right out.

Put a hole in a straw and then blow thorough it. The cover the whole and blow through

 

"The wastegate won't matter as it only opens when told to by your boost controller."

In the words of "Larry The Cable Guy", Now thats funny, I don't care who you are.

 

Fix the hole in the bucket before bothering to add more water.

 

I agree, If your boost is coming on that late (4500) there either an exhaust/vacuum leak or a tired wastegate. Boost should come on near 3200- 3400.

 

That is what I'm hoping. So we'll see if the catbypass pipe and new exhaust make a differance next week. I might need to get a Tial wategate too.

 

The first thing I would do is make sure that the Autothority chips are for the upgraded 26.8 turbo, and not the chips designed for the original 26.6 turbo.

The right chip for your car's set up is paramount.

 

Are you only getting full boost at 4,500 RPM (when, let's say you floor it at 3,000 RPM) Do you have a working boost gauge? The stock one is fine for observing when you get full boost.

Or, is it that you just feel a general lack of throttle reponse and crispness until about 4,500 RPM?

I'm going to assume the former.

Before you throw money at it, it's absolutely inperative that you locate and fix all leaks (exhaust and vacuum/boost) first, otherwise you're just chasing your tail.
At the same time, you upgrade your exhaust (which you are doing), making sure that your cat is removed as that is the biggest exhaust restriction.

Unless you're not getting the 12 to 15 psi boost (depending on your chip kit) at ANY point in your RPM range, the wastegate is not the problem. And the chip is also not the problem.
A new wastegate will help with mid throttle "feel" but generally will not help with boost threshold when you put your foot right to the floor, which I still assume is the problem here.
Check all the basics first (leaks, exhaust, ignition components in good working order, turbo in good working order)) and then you should be getting full boost at 3,200 to 3,500 RPM.
Only then can one take the next step for more power and /or boost reponse via MAF, different chips, possibly turbo, wastegate, etc.

 

I noticed a difference with my Spec aluminum flywheel and lightweight hybrid clutch disk. But that's an incredibly expensive method of gaining better acceleration. I did it because my clutch was busted and was coming apart anyway.