I've got the PE exhaust coupled with PE software and the sound is perfect - it is more aggressive than the Dinan exhausts that I have heard. For me putting the PE exhaust on my car enhanced my whole experience with driving the car - I love how it pops and crackles on deceleration and between shifts and wails exotically in the upper rev ranges. I drive whenever I can with the windows down to hear it.
While I don't love the tips on the PE exhaust, I really don't like the cheap looking double walled tips on the Dinan.
I get a tiny bit of drone at low rpm on the freeway, but it doesn't bother me at all.
You can't go wrong with either unless you are looking for a much more aggressive sound.
Performance Center Delivery, June 21, 2013: 2013 E92 335is | Le Mans Blue | Gray Leather with Black | 6MT | 19" Style 313's | Michelin Pilot Super Sports | BMW Carbon Fiber Rear Spoiler |