I just purchased this and installed it last night

http://www.meganracing.com/products....asp?prodid=151

Megan Hi flow cat/down pipe/test pipe. What is the proper term for this? Megan calls it a hi flow cat, and a test pipe, and a down pipe...lol. Just wondering what it really is.

Was it a mistake to put it on. It makes my car loud as hell, my CEL came on which I'll take care of tonight. But everyone says it would make me lose power because I'd lose backpressure. Will this pipe really make me lose backpressure? I think when I was asking about test pipes before everyone thought I meant just a straight pipe....