I have been looking mostly at the Megan cat-back exhaust and the Borla. I have listened to a few sound clips of both and really like the sound of the Borla but I really like the price of the Megan. What exhaust is has the best performance gain? Is replacing the oem header worth the cost?

 

Borla is the best sound for R50 from clips I've heard.
Cam + Headers + free flow muffler exhaust + better flowing air filter are probably your best options for R50.
A light wheel @ 15 lbs each or less will be a big help on acceleration & breaking & handling.

 

If I go with the free flowing exhaust how can I get rid of the check engine light code that pops up with removing the catalytic converter?

 

Don't rule out a Milltek catback, or even header if your budget allows. Great price on the catback at outmotoring.com and made in England, just like your MINI!

Bought one on black Friday and will be installing soon. I'm expecting modest gains probably about even with the other catbacks, but without any drone. From what I've heard, Milltek is one of the quieter ones available. Can't wait to put it on.

 

Does anyone know about the codes it's going to throw up if I remove the catalytic converter?

 

It will throw codes. In many states you can't remove the cat. Cat back systems work with a cat in place. I have an r53 cat back from UUC. With a Dinan air box, it makes a huge diff.

 

I don't live in a state that requires a cat. If I get a header and a cat back system am I going to need a text pipe for between the two?

 

You will need a bypass pipe. I don't see any real benefit anymore to removing the cat. Modern systems have minimal loss. Taking it out leaves you with codes, and a fuel system with a big piece missing. It looks at the precat gasses and the post cat gasses to determine mixture. You really need to spend some time talking to reputable shops that have done this, and get feedback. Which system do you want that requires gutting the cat?

 

I want to replace the stock header and run a Borla exhaust but if removing the cat won't make much of an increase in just get the Borla cat back and an obx header with cat

 

Choose based on the sound you like best. Real power difference between different exhausts is negligible. It's hard to get significant extra power from the R50 engine without major modifications. I'd recommend an ECU tune, which would give you a flatter, more responsive torque profile.

 

Would the borla bolt up to the Megan racing header?