Hello and welcome, there are a few quality/detail issues with SDS (Shepperton Design Studios aka originalstormtrooper.com), this thread may help you, @Helotech put in a lot of rework on his SDS kit, most mentioned in his pre approval thread
Also his build thread
Another SDS pre approval
Just takes a bit of work to get them to an approvable costume but I'm sure with garrison help you will do just fine.
Good luck and any questions please let us know