Please please please remove the rear trailing arm bushes and use the GGR ones.
Poly bushes are a massive downgrade over the factory spherical joint bushes. I can promise you 100% your car will handle shit, wander and clunk because of them.
You'll end up hating the car. I have replaced all mine with the GGR bush and they're just far superior. I assure you what I am telling you is the best and only way to do it. There's plenty on here that'll agree.
Just don't want you to build the car to then not like it due to that reason. Whilst stuff is easy to remove I'd seriously suggest doing it and changing them.
Can you add a link to them