May I suggest that you forego your dad's "custom exhaust" and spend some money on a quality cat-back for your honda. You have no idea how a home made exhaust is going to sound, how loud it's gonna be, or how it's gonna hold up (not to even mention whether it's actually going to make your car slower by robbing it of horsepower.)
I put a custom cat-back on my '99 Civic EX made by OBX Racing that was purchased from
http://www.massive motorsports.com/ and I am really happy with it. Yes, it's louder, but it sounds great and the car has a noticeably faster pick up. It's a good quality exhaust that you should be able to get for about $350 (shipping included.)
You will be much happier with it in a long run and it will save you money as well. Everybody has a different budget, so spending money on a $600 Apex'i exhaust was out of the question for me. No doubt, Apex'i exhausts are some of the best systems out there, but to get one for an older honda would be an overkill, in my humble opinion.
So, save some money on install and have your dad put a quality cat-back exhaust on your car instead of trying to make one for you instead.
You will be glad you did.
drumboy69