BRAND NEW, still in box and wrapped Audi A3 8V Unitronic catback exhaust with resonator! I ended up selling the car so my loss is your gain. Never installed or even taken out of the box. 
This will fit any Audi A3 8V 2.0T Quattro, Ebay won't let me list the earlier models (trim level is missing) but this will fit 2015-2021 (depending on if your car shifted from 8V to the 8Y chassis during the 2021 model year). Local pickup in the Spokane, WA area is welcome, and will avoid the shipping fees. Please DM if you require more pictures. 

From the vendor:
https://www.ecstuning.com/b-unitronic-parts/unitronic-cat-back-exhaust-system-for-8v-a3-quattro/uh028-exa~unt/

Like all of Unitronic's Performance Exhaust Systems, a unique v-band fastener system, using T316 Stainless Steel flanges was utilized to ensure a leak proof connection every time. This is achieved through a locking ring on all Unitronic v-band flanges to guarantee a centric alignment of the two flanges. Unitronic's mufflers feature a high density, high temperature glass fiber packing and are stamped with the Unitronic logo with a straight-through, free flowing muffler design.

These attributes combined ensure maximum performance, while maintaining a comfortable and unobtrusive tone inside the cabin. Exiting at the rear, exhaust gasses pass through dual 3.5" Double Wall Polished Exhaust Tips with Engraved Unitronic Logo.
Features / Benefits
 
3-inch T304 Stainless Steel Mandrel Bent Tubing:

• Quality Material that will not rust and will outlast your vehicle.

T316 Stainless Steel V-Band Flanges:

• Durable, rust proof and cnc machined.

Direct Bolt-On Fitment:

• Use all factory exhaust hanger and doesn’t require any modification or adjustment.

TIG Welded Construction:

• Professionally TIG welded to ensure longevity, durability and top tier craftsmanship.

Unique V-Band Fastening System Featuring Clampco® clamps:

• Maintain a perfect alignment of v-band flanges while ensuring a leak-proof connection every time. Fully reusable and quick to install.

Universal Fitment:

• Come with OEM size reducer for a direct bolt-on. Optional 3” adapter available for any after market exhaust system or 3” slip fit adjustable link to match to any Unitronic exhaust system.

Sound Reflection Chamber Technology:

• Sound reflection chamber used to cancel unwanted sound frequency and ensure a deep tone.

Sound Absorption Technology:

• Perforated chamber packed with High quality and durable high temperature Fiberglass wool. Ensure a deep tone and unwanted frequency absorption.

Straight-through, free flowing muffler design:

• Optimal performance achieved by removing restriction and reducing back pressure.

3.5-inch Double Walled Polished Exhaust Tips:

• Mirror polished tips engraved with the Unitronic logo.