Who knows cat-converters?

[DSMopar]

I'm going to be putting a universal cat on my Apexi N1 exhaust and would like to know what's the best bang for the money. I know next to nothing about cats and I was surprised at the wide range of options from summit. There seems to be different substrate styles;

* Ceramic honeycomb,
* Monolithic catalyst,
* Metallic honeycomb,
* Metal substrate

Out of these which is the best substrate for flow? There also seems to be a vehicle weight rating (i'm assuming for a rated life based on emissions). Also some have air-tubes, I've heard that you can't just plug the air tube or they'll burn up, is that true? Out of the ones they have in stock here's a couple i'm looking at:

Catco 2407W - Catco Universal Catalytic Converters - summitracing.com
MagnaFlow 94009CA - MagnaFlow Universal Catalytic Converters - summitracing.com
Dynomax Performance 15143 - Dynomax Super Converters - summitracing.com

The dynomax sounds the best as they do sort of give it a flow rating by stating it can handle a 460 cube motor but also it is the most expensive. Also keep in mind this isn't just for appearence, it does actually have to perform so my car can pass smog. So which would you choose?

 

[Avionixx]

Any material except the metallic honeycombs or substrates; they may work great for flow, but stink when it comes to passing emissions (assuming this is why you're thinking of a cat in the first place).

The air tube is just for cars equipped with air injection and you can block it off; these converters are made to be used on several different types of cars. Though I'd get one without the tube just so it'll look nice and clean.

 

[DSMopar]

Any last minute suggestions before I order this tonight? I'm leaning towards the magnaflow