i wanted to do some simple mods to my STI, some like new cotton filter and some other stuff, can some one recommend some simple things i can do for some extra power and where in west london would be a good place to get these things done, thanks

 

A good panel filter for a start, I would stay away from the cone filters as it seems the maf sensor dosent like them, next would be a good exhaust and decat... To get the most from these you will need a remap with can be expensive...

 

You could go to TSL and get the 333 package for £2100. This includes remap, panel filter and walbro 225 fuel pump. It gives about 333bhp and 335lb/ft torque.
Or you could buy the items seperately for under a grand and get it mapped somewhere else for about £600, thus saving you some hard earned. If you are going to upgrade, then change the oil pump as well to be extra safe.

 

Power Engineering in Middlesex have always done a decent job on my scoobs in the past and if you want to travel take it to API in Leamington.