the Racing Beat is by the far the best exhuast if you plan on only a few bolt-on mods...The 2.375" diameter is excellent for a decent kick in power across the entire rev band for a minorly built FS...it it s fairly heavy system, but has excellent exhuast tone
HKS and 5Zigen offer bigger (2.5" or more, excluding the slightly larger than stock HKS axle-back) cat-back systems for around the same price, both being a little more expensive...these will not help with lowend torque, being bigger in diameter, but will help with high rpm breathing...(simplified: you may see a higher peak output with the larger exhuasts, but you will not gain or could loose a little lowend torque)...both of these systems are a little lighter than the RB, but have much more of droning sound at cruising speed, and may have a raspy (rice) acceleration tone..
The MSP factory sport exhuasts are more for sound than performance gains (but you still may pick up a few hp)...I have no experience with them...