A couple months ago I bought a 99' Accord. Everything else was great, except it didn't have exhaust on it. It had a piece on there that was made to have dual exhaust, so I went out, bought the mufflers, and took it to a shop to put on. It sounds good and all, but by converting it to single exhaust, would this make it louder  ?  

the sound of the exhaust wont really change at all.  it really depends on the exhaust itself.  i had a stock dual exhaust and bought a single pipe exhaust but it didnt really make any difference.  mostly for looks.  it all depends on your resonator