Ok...so I have a bad cat and need to replace right exhaust manifold. I've seen the magnaflow exhaust manifolds with high flow cats, for about $520 a side, and was told about the PPE headers via CL for this car ( 2006 GS300 )

I have yet to read any reviews from anyone who has actually installed them on a GS300. I saw a clip on an IS250, and clearly they don't sound alike.

I have a DC Sports intake, and a Tanabe Medallion Exhaust that this will be paired with. I found a LEXUS OEM manifold for $800 for the one side, but if the cost of a dual set and HP gains are there, I'd spend the extra,... but I'd like to know how it's been for those who have done it.

Noise

Leaks

Fitment issues

O2 sensor issues

Build Quality

HP Gains

Any input would be greatly appreciated