Best glasspack to run?

I personally never liked round mufflers. When i wanted to build a shorty/removable system, i just used some 2.5/3.0 straight pipe into a good turbo style oval with a cheap hanger on the back. Reasonably quiet with good flow. If this is for your p/u, you got plenty of room to experiment. That's just me, but i'm really old school. :)