Evora

The normally-aspirated 2GR-FE V6 motor isn't exactly endowed with sparkling performance, so anything that helps it to breath better will help!

The OEM silencer is the heaviest I have ever come across on a car - 23Kgs! Most dealers have removed it and fitted the Lotus Sport system to at least improve the soundtrack.

For hard-core enthusiasts, you need to tackle the restrictive OEM headers(manifolds) and downpipes and fit a large diameter 100cell catalyser further down the system.