Having a Bonneville would seem easy and speed free to most. (Gramma car right?) Those of us that once got bitten by the mod bug know there is only one cure. More mods.
My latest is PEM'* from Hulkspeed. While doing most of my mods, I strive for the factory look. Currently the blue vacuum tubing is bothering me. Anyway, on with the show. Opting for the porting and ceramic coating was the way to go in my case. A variety of colors are offered.
Front and crossover
The change is very subtle and most people won't notice my manifolds aren't rust looking.
This picture shows the difference in the front manifold
And the change from rust to ceramic coating.
All three pieces
Currently the back manifold did not make it on. The exhaust pipe to manifold bolts refused to give and I have a buddy with a lift and torch. The rear exhaust manifold flows well from the factory as you can see it is tubular in it'* design. There is a difference. I wouldn't say I noticed a huge butt dyno difference. The acceleration is smoother and pulls harder. KR is lower than before. As a supporting mod, this smoothed things out nicely.