My personal experience is that fitting a K&N filter along with an aftermarket tail pipe more or less got rid of the flat spot in the rev range. Adjusting the TPS and balancing the carbs made a big difference to how smooth it was afterwards too. Not sure if it gave any more power. no changes are required to the jets as it runs rich as standard.
As stated above, most people that have tried pod filters have had loads of trouble trying to get the jetting right and probably ended up with more noise, but less power than they started with.
