Checkout humblemechanic latest video to see what issues he's been having with the updated bushes before making a decision.
Different bush style and chassis loadings. Time trials are really hard on suspension. Poly was never a good idea with that platform anyway. Either OEM TT rubber bushes, or spherical bearings, but defo not poly! The MK5 is different as it's just rotational and fore and aft loadings. The MK4 rear wishbone bush was subjected to loadings from all planes and is just a pants design. Interestingly, the MK7 has gone back to that
Cheaper to build than console housings though. Always comes down to cost.
I can't stand poly on road cars. I've said it many times, it just has no place on road vehicles. You can get away with it on the console bush but every other bush should be rubber, imo. Poly just cannot handle the loadings rubber can, and it suffers from creep and set.....in other words, once it loses it's shape and elasticity, it's no good. Creep and set happens on the console bushes. The hole the for the wishbone stub ovalises and causes awful tramlining.