Metric BJ4?
 

It seems like the SAE screws strip the plastic parts on the car much too easily and was wondering how much modification, if any, was necessary to outfit the BJ4 with metric screws. Only looking to do this to the gearboxes and I do realize that the holes will have to be enlarged slightly, though I'm hoping that I won't have to change the countersinks in the carbon and aluminum parts to get the screws to sit flush.

Will 3mm screws hold well enough to consider this a worthwhile mod?

Putting an M3 screw in to a stripped 4-40 hole is quite a common fix.

4-40 screws are appx 2.85mm dia - M3 screws are 3.0mm dia

I realize the 3mm screws are larger...just wondering if I'm going to have to enlarge the countersinks in order for the new screws to remain flush with whatever carbon or aluminum parts they'll be going through. I don't have the car and new screws sitting in front of me at the moment :D

Thanks for the reply!

UPDATE: metric screws work great in the gearboxes; tight fitting even when the holes have been stripped by the standard hardware. No real modification necessary, only had to ream out the upper plate spacers slightly.

Maybe you need to try not kranking the screws up so tight, it wont take long for the M3 screws to strip out the threads aswell if you are a bit heavy handed. My old BJ4 didn't have one stripped thread in it after 2 seasons of regular stripping and rebuilding.