speedway mtrs (1 mile from me) has a kit of 1/2" ID washers of varying thicknesses for a few dollars (flat with no sharp edge on one side). You want to shim the collar with the roll pin so you are down to .005" axial play and peen the dist lower shaft tang so their is no rotational play in the rotor (lower shaft), check by twisting the rotor back & forth (before and after you add the collar) LIGHTLY just not enough to get into the springs & see how much you are dealing with. Also you can shim under the mini clip on top a bit so the slot will not come off of the pins which is helpfull when removeing the reluctor cuz having the slot plate and the flat plates and the rotor all coming out as an assy makes it much harder to then remove the reluctor with the assy out of the dist & it in your hand. If you dont press down on the top shaft when removing the reluctor & it comes off of the pins then you know what I mean. You need some clearance there so you can get the C clip in/out but you can reduce it. I ain't done it yet but adding a cup oiler on the side I think is a good idea & they are available seperately. last would be to mod the magnet & possibly the plate hole location for the can arm so there is minimal gap change as the can shifts the plate, Nacho got it down to .001" not sure exactly how he did it but its on my list.