My advice would just to be careful which one you chose.
items such as the K & N cone filter come with such promise, and completely fail to deliver for the following reason...
it sounds like a good idea to junk all that ungainly stock airbox, and certainly this can be dramatically improved upon, but the K & N kit as i learnt with my old 2.0 TS was nothing more than a cone filter attached almost directly to the MAF hose, and a length of corregated vent hose to patheticaly aim cold air from somewhere, anywhere at the front of the car to direct that huge gollop of cold dense air you're chasing after right up to the nose of the cone, Fabulous? NOT!
the position of the cone sits very high on the TS motor, and it suffered terrible heat saturation as a result. no amount of ducting could keep the element from absorbing and swallowing litre after litre of warm bone dry air from inside the engine bay, and nothing from outside whatsoever.
the real world result was that day to day, in traffic or just driving normally, it was a nightmare, coughing and stuttering at low revs, stalling if held at lights or an island a fraction too long, etc etc you get the picture!
if all roads were alpine autobahn, it could have worked, potentially, but in the real world, it sucked, literally!
more noise, no go, ruined an originally sweet running car that ended up going back to stock airbox with performance element inside it.
the only type i will entertain now, is either a free flow filter in the stock box, a cone filter IF it can be routed and sighted well away from the engine heat, which is often impractical, or possibly the best compromise, the BMC CDA.
these take the idea of free flow filter inside a semi pressurised airbox a stage or two further, by being constructed of carbon fibre, the heat rejection and dissipation is great, and by being under similar air pressure by following a simlar intake route to the stock airbox it is well out the way, and will not upset the quality of the running at all.
gain gain gain i think?
lightwieght too, more cold dense air at a slightly increased flow rate, better filtration, and a one time purchase as the elements are washable, oh, and pretty trick looking too!
they are about £150-£200 i believe, which is why i don't have one myself yet, but i will have, and soon...
give the BMC CDA a look up, there is a lot of info on this forum about them too, see what you think to it.