KA24DE-T, downpipe to exhaust

[GTS]

I've got a 2.25" downpipe + 2.25" Magnaflow cat + 2.25" exhaust right now. I'm considering a larger exhaust without changing the downpipe and the cat.

Basically, it would be a 2.25" downpipe to the cat to the 3" HKS Hi Power. I have the Greddy Bolt-on kit which is infamous for boost creep when one increases the downpipe to 3".

I'm wondering if it is okay to go 2.25" DP -> 2.25" Magnaflow cat -> 3" exhaust.

Will I encounter any kind of boost creep?

Are the gains worth the change? If so, what kind of characteristics will I see (low RPM power VS high RPM power?)

Thanks