Here's a bit of experience with exhausting anywhere but Behind you. A friend of mine bought a 69 Firebird in 75. He told me he wanted his mufflers to dump down just before his rear end. I told him if he did that the exhaust would eat away the underside of his car. All these years later there it sits in his garage due to the trunk and entire rear underside of his car is now eaten away, including a huge hole in his truck. His car would need a complete sheetmetal reconstruction of the rear end from the corrosion the exhaust caused. On the sidepipe idea, it's bad one, even the mopars that came with sidepipes were and are known for the exhaust eating away at the sheetmetal as the fumes are sucked underneath the car. Your tires will also quickly rot away from the exhaust fumes. These are GREAT reason's why almost all cars have rear exit exhausts, just my opinion though.