Neither

Silicone won't be strong enough,you will need to use Tecflex or some other brand of seam sealer/car body bonding stuff.

Don't use pop rivets,the splitter is fibreglass and the shock from the rivet gun will crack it all to shit I would think.

I used small stainless allen bolts and lock nuts and washers on mine

I gave up trying to fit my Moose one and sold it,bought a gen RS500 one that had been chopped down to fIt a Saph,much better IMO.

Rouse ones look like snow ploughs IMO!!!!