Jim Clayton's heads are highly regarded here. On something like a rev400 kit they might net you another 20hp (assuming other elements of your system are set up right). To get the most of the rev400 you will have to upgrade transmission and clutch. You need to look up engine internals as well. Google "2zz-ge glass engine" to get details on the parts which need beefing up.
Storm titanium 2005 Elise with carbon fiber spoiler, BWR sway bar, BOE toe links, gPan2, LidBone, sector 111 wheel studs, Grey RAC Monolite wheels with toyo R1R, Team Dynamics 1.4 with Hoosier A6/R6s, Katana2 Supercharger, ECU with 265 flash. PPE headers w/decat, CEL angle eliminator, Silent touch catback, Rear Panel Eliminator, HKS intake, V2 fuel tank, Walbro255 fuel pump. HID lights.