For information only - this is why your factory exhaust sounds so bad.
The Cup 220/250 uses the same shell as all the Toyota-engine installs. Interesting to see the end-cap seams welded up - different from the old 111R silencer which had rolled/folded ends. Obviously more gas-pressure to deal with on this supercharged install. It has a double-skin to control drone on such a large open chamber. Makes for a heavy unit though - 16.4Kgs.
Looking at the internals, it's a typical Z-flow arrangement helping to control NOISE emissions. Each end has a double-walled chamber filled with stainless wire, again to help control drone. Early 111R silencer had fibreglass filling but it used to melt into little glass balls!
The entry pipe is reduced from 63.5mm to 57mm, so quite restrictive for a supercharged motor. The reverse pipe is 60mm and the outlet pipe is back to the full 63.5mm. You can see the entry to this final pipe is not straightforward - gas-flow has to come back through the mesh screen. Holes punched at the entrance of that pipe increase the area for gas entry. All features to help break up/disrupt the sound waves/energy.
I had a couple of attempts at developing a new 4-1 manifold for the 2ZR motor. It's ok increasing the bore diameter from the factory size for more power but the torque as it came out the factory was VERY good. It can be difficult finding a willing test-mule here in the UK but Daniel Koblitschek, owner of Komo-Tec GmbH found a Belgian 220Cup owner who allowed me to test the latest 2bular 4-1 on the KT dyno.
Below is the 45mm 2ZR 4-1 for the 1.8Ltr Elise S and the 220Cup.
http://joetaylorracing.com/ along with https://www.facebook.com/RRR.Engineering/ have worked to develop a stand-alone ECU for these cars and the later 250/260 Cup cars - with hugely impressive results!
I hear Greg Lock (MD of Hangar 111) had a bit of a melt-down when he was told his 2ZR manifold came off second best in testing! Never mind Greg, stick to buying domain names.