the ones from the factory
if all you get looked at is a CEL then you can tune that out, but if they were to actually measure particulate. nope.
cat back? sure plenty of people do it.
obviously LSAs come with cats from factory but depending on your intended power levels, you will likely blow out the cats if you plan big numbers.
The plan is to supercharge it and stay under 450rwkw.
A number of tuners I spoke to want to cam it as well in order to relieve some cylinder pressures. Other tuners say the SC will work fine with the factory cam providing it's tuned accordingly.
One tuner says he can do SC, high flow cats, AND cam that will pass emissions no probs, I'm guessing an E85 tune.
Re: the cats, I'm leaning towards 200 cell although most tuners warn against them in case of a failure with SC applications, mainly heat issues disintegrating them.
Decisions decisions.....
PS. I've heard it mentioned that most aftermarket high flow cats are shitezner for durability anyway.
So, how to find a cat that will pair up well with a SC, be relatively not fumey but not disintegrate either....