Their first gen knuckles had a weak spot and depending on your track when turning into a corner the front tire is exposed to impacts and this car really turns hard so you will hit the tire on objects. They have a newer version out that is stronger. The A-Arms in teh kit are very hard but you can get softer ones which will also help.
The hard bumper it to protect the suspension from hits. the hard one just protects better
CVD's are what comes with it and it comes with a selection of toe mounts I believe but I got one that was already built.