I haven't seen these anywhere.
Is there a reason why they are not available?

 

mG - Probably because the factory dual cat/pre-cat system is so good as it is. Been told by several tuners ( SRT & RMM, amongst others ) that there's not a lot of HP to be found in the GS exhaust system except for the mufflers as they are designed to be quiet as opposed to free-flowing. I picked up 8 rear wheel HP by changing to Borlas & someone else used the GReddy's to get 12 HP ( GReddy's a true cat-back system ). But change to Mo's HFI & there's 20+ to be found there! I called Random Technologies ( who make racing cats ) & they don't have or plan an application for the GS.