P0420 and downpipes

[rsmoove]

Hey guys,

 

I'm looking for some advice. I've been trying to get rid of this p0420 code for a few months now. I've replaced both O2 sensors. Subaru for the front, Denso for the back, and it's had no effect on the CEL. I'm pretty convinced by now that the cat itself needs to be replaced. I was about to try that lacquer thinner in the gas tank thing, but the more I read about it, the more it seems like it's just a temporary solution, and will do more harm than good in the future.

 

Here's the deal. I don't really want to go the whole catless route, because I don't want to have to buy a tuner and have the car tuned. Is the best/cheapest option (or most cost effective I should say), for me to go with the Invidia catted DP? I was hesitant about the Invidia because of having to modify the divorcing separator to make sure there's clearance for the wastegate, but I heard they fixed that so you don't have to make any changes. The Cobb DP looked cool, but was a bit expensive. I really wanted the ERZ/CNT DP, but I can't find any in stock for the automatics and nobody knows when they're going to have them again. I was looking on Rockauto for a "close to stock" option, but I don't really see a DP for an automatic GT, only the manual. Actually, when I look for downpipes that aren't aftermarket performance brands, it seems like everywhere I look the majority of options are for the Legacys with the left and right catalytic converter setup, which I don't have.

 

I've been kind of surprised at how few options I've seen for this predicament, so I figured I'd try to see what you guys thought.

 

Thanks!