I have the original 525 mags which were the fastest ones made, the super and the extra came with the extra mags to calm them down a bit !!
Mine are fine however on red rocket oil and a mag setting of 4-6 depending on conditions. Are you sure that you havnt dropped a amgnet out accidentally when you have had it stripped down Davo ?
Line diameter and loading can have a big effect on the 525s too. If you fill them to the top with any line below 0.35mm they will be frisky no matter what you do with them, as the line level does not drop fast enough through the cast and the extra spool weight and inertia will always be supplying too much line.
.35mm is ok but only fill the spool 3/4 full
.38mm is better but still fill just below the spool shoulder
I use mine off the rocks with .43mm and fill it right to the top and it is fine like that

Sorry if you already know about all this Davo but I mentioned it in case anyone out there with a 525 is struggling too !!
Rob