Whats the best glow plug for the vx .16 engine?

It really should not matter, any cheap mid-heat range plug will suffice. Since this is an RTR engine (a cheaper one at that), there is no need to waste your money on an expensive $8 glow plug. Just find one that is a medium temp range plug and you will be okay.

I use mccoy or o.s. hot plugs but cheap hsp ones work good to.

Thank you for your post.