Best bet but most expensive is the k & n typhoon kit, check most online retailers eBay etc.
There are quite a few options but the long arm kits seem best. Funky power have a bit of a selection but the widest range is available in the US. A few guys on here have imported kits.
Fahad measured a 12bhp increase with the typhoon kit !
Steve arcade has also posted an excellent DIY intake guide on this forum. Well worth a look.
Or get some 3ich plastic drain pipe with a 2x45 and 90 degree bend.stick k&n filter on the end.should also perform better as is wider than the typhoon kit
it actually measured 205.9bhp from memory.. but I don't have any 'before' runs to compare it to, and typically these K24's run higher than the factory quoted 189bhp anyway. But in any case, it definitely makes a noticable gain on power and torque.