Elise S 1.6 1ZR-FAE
Lotus's nod to the Green lobby perhaps. Certainly needs a bit more oomph. The OEM silencer is HUGE and muffles any character out of the exhaust note.
The standard 2bular offering is the 7"dia x 20" system and this seems to be the one most in demand. Be aware that 2bular is the only firm who designs and makes an exhaust specifically for this car. It has a bore matched to the output of the 1.6 engine, allowing best power and torque.