camo, this is what I will tell you: An open exhaust can net you more power, but it can hurt your low end torque. The wider you make it, the louder it will tend to be and normally result in better high RPM power, but it will also hurt your torque at the low RPM since there will be no back pressure on the cylinders.
So, I ask you, do you spend more time at 1500 RPM or at 5,000 RPM? You run a really free exhaust and you can plan on your city mileage dropping into the single digits easy. Highway may improve by about 1 mpg (maybe). For most people, they see an overall loss of mileage. So, now, is the loud sound more important that mileage. that is only an answer you can make.
As for installing the muffler, yes, you can clamp it in place, just have to make sure that the clamps are tight and you get plenty of overlap between the two pipes. You get that and you should be golden.