I have a pair of pretty short blue streak gl***paks on my split 6....gets lots of compliments and isn't too obnoxious (the straights I had before were way too loud)
I have set of Fenton splits on mine with Cherry Bombs dumping out before the rear tire. Sounds pretty good but I always wondered how much different it would be with Smitty's? Pipes are 2".
I like my generic gl***packs on my 250. You results may vary. I agree with brewsir-my open headers were WAY too loud.
I also agree, the best sound on a six is 1 3/4" straight piped right out the back, all my cars have straight pipes and it may be loud outside of the car but if you run them all the way out the back it stays nice and quite inside.
Here's how the Bombas get that raspy growl: run a 12" glaspack on the original outlet and a straight pipe on the side where the split pipe is. Keep them airtight to achieve that popping thing. Straight pipes usually sound like a broken car.