Molded Tyre inserts-yay or nay?

[Gustav]

What are your opinions/experiences with these on your monster trucks.Is there a performance improvement and is it worth the considerable weight penalty?
are any pro drivers using them in truggy or MT racing?

reason i ask is i just got some for the first time,they definately feel like they'd improve consistency and even grip level but they're dang heavy.I measure 188 grams weight penalty for four maxx/MTR inserts compared to foams.These are the fastrax extra soft ones,they look the same as the proline ones to me(never handled the prolines though)exept they come in different colors,soft and extra soft.If you remember nerf toys,nerf balls and stuff,that's what they seem to be made of,it's not light.