2 biggest killers of MAF sensors are Vibration, due to incorrect fitting or Contamination, due to the filters inabilty to filter small enough
I recommend you go down to Maplins Electronics and buy a Multimeter. Then every so often, possibly every day, check the voltage on your MAF sensor. Pretty much guarentee that the voltage at the MAF will die soon due to being contaminated with oil from the 57i kit.
The oil used in a K+N filter is a very fine Duck Oil, they coat the filter with this oil to prevent water entering the engine. When the car pulls max boost, the airflow going into the engine is strong enough to draw the excess oil out of the filter and with the MAF sensor being so close to the filter it gets coated in the oil causing the sensor to burn out or give a false reading. The ECU in your car uses the MAF sensor when you go over certain perameters and if the signal from the MAF is reading low due to the oil from the filter then the resulting consequences will range from Check Engine Light to Limp Home mode and if it fails with your foot on the floor then a severe vibration through the pedal and loads of smoke out the back end.
Apexi Power intake filters are the best for the balance between airflow and filtration of particulates but the only make them for the standardish horsepower cars. Once these filters become the limiting factor in potential horsepower then it is advisable to go for the larger Grp A style cone filter.
Best filter for airflow is the Blitz SUS filter, downside is the filter does not deal well with the filtration part of the job
Best filter for the job of filtration is the K+N cotton filters
Playsatan forgot to mention he runs a item called a MAFSIM, this item does away with the MAF sensor and instead uses a box of Voodoo magic to give the ECU the correct MAF values for the given load situation.