I have had 3 MG Zr's, 2 1.4 16v and 1 2.0L Turbo diesel
Basically in a nut shell the 1.4 16v K series is factory tuned to the max right out of the factory with its 105 bhp. Fitting an open cone airfilter will give the engine a lovely growl and make it sound faster but you will lose a few horses...