Again, these systems use straight-flow mufflers and resonators, with not much muffling, hence the "loud mouth" system advertised.

The e-mail from SLP reads:

Thank you for your interests in SLP Performance Parts and Ford Mustang products.
SLP will be offering our new Mustang Axle-Back exhaust components with-in the next few weeks. SLP will be offering both Loud Mouth and Power Flo versions to give our potential customers a choice.
Also, you may want to sign up for our Mustang contact us on our web-site, as we release new Mustang components, SLP will e-mail you releases, specials, pricing, text etc., keeping you informed of our progress.
I hope this helps.
Sincerely,
Kevin Woodruff @ SLP Performance Parts
Tech/Sales Manager

If you're interested the address is: http://www.slponline.com