I have only heard two exhausts on civic that actually give it a good deep sound without popping or tin can sounds and those are greddy and DC. I personally have a dc sports on my car and it sounds amazing, its by far the best. the greddy is good also, but it's extremely loud. the D.C. has great sound, and it isn't annoyingly loud. i always get compliments about it. people are amazed how good it sounds inside and out and how quiet it still is. they are expensive but its pretty easy to get one used i got mine for $230 off of civicforums.com. good luck!