A grind involving the vehicle "Infernus"
So Can I use it for a grind to? (Do the grind with the actual infernus).
No
the word "involving" can totally turn around the meaning of the stunt.
By saying involving it doesn't mean he HAS to do it with the infernus but the infernus has to somehow take place in the challenge.
Example - a psm needs another vehicle to become "stuck" but instead of of any random vehicle an infernus could be used to make it "stuck" which is making the infernus involved in the stunt.
Good job kooz i liked it that you used a stuck method. and i think the grind added the spice the stunt needed