That erz cnt down pipe looks good and the price is reasonable, you'll need the $30 adaptor if you are running a factory like donut style intermediate pipe. That takes you into the $400 range. A high flow exhaust with a factory 3rd cat may cost you 5% in power loss. Say 300hp with full high flow exhaust or 285hp with the slight restriction of a factory 3rd cat on an otherwise high flow exhaust system. If you ever plan on going with a bigger turbo and higher hp you definitely want the bellmouth full length down pipe. If you are just going stage 2 for improved driveability keeping your stock td04 turbo, you'll be just fine with a stromung shorty for $169 and bolt your stock 3rd cat to it. I have a stromung shorty on my 05 saabaru with the stock 3rd cat, stromung 2.5" intermediate and a prodrive 2.5" oval axleback runing on Cobb stage 2 for several years and it is a very torquey exhaust. You can run a 300 hp wrx on a 2.5" exhaust. Look at the oakos project bugeye for example. I've had a full Cobb turbo back on my saabaru before the current setup I mention above, if there is any loss it isn't even noticeable. I did however feel the difference in stronger torque at low rpm's with the stromung shorty, the divorced wastegate design works rather well and never had boost spiking or any monkey business.