IS200 Power gains without loss of reliability

I just wanna start off by saying I am new to this forum so I'm sorry if this is a repeat of a previous thread. I have just become the proud owner of a 1999 registered Lexus Is200. And I have to say so far I am very pleased. After being a VAG (Volkswagen & Audi) Driver for so long it feels nice to get into something a bit more responsive and it feels even nicer to turn the traction control off every now and again and get the arse out on a few turns.

My only problem is the car leaves me wanting a small bit, I need more POWER!!! its the standard 155bhp model and although its responsive and reasonably fast (compared to the diesel lumps I am used to) I have to admit I would like to try get it up and over the holy grail of 200bhp. I know that is reasonably easy, Just stick a supercharger on it, but I would rather not do that because after getting 55mpg constantly from old VAG diesels I don't wanna be hit too hard in the pocket in terms of everyday driving.

So what I really need is to find is some aftermarket products that can give me the extra 45+bhp I need without making the car a gas guzzler or affecting the solid reliability you would expect from a Toyota manufactured car.

P.S I am from Ireland so I would appreciate any help finding products that are available here or in the UK. Thanks for your help in advance.

Quazzie