I am building my FRS into a T4 this off season as well so you're not alone.
You're correct on the suspension. You have to use that Eibach kit (Spring/sways) on the FRS - different cars get different options and
non adjustable shocks that have a P/N stamped on them.
The popular option are Bilstein B8s but MCS and KW both have made non-adj shocks with OTS P/Ns for the cars they are sponsor (Dynasty FRSs in Florida and Oscar Jackson in California). Oscar uses the KWs.