Decat and straight through is a win, a member recently made 90bhp with that but 2 or 3" decat back I'd defo say don't bother with a mani though, on the last Dyno day I made more power than one NA using an adapted corolla exhaust mani and another using a OBX AND decat! Obviously it depends on health of engine etc but it's best to go with something proven Ask redz11 about the Glanza TB, or miib14 they both have them I think