The Ralliart thing... I can see it. The 2.5L WRX is already in STU. The EVO, even though it's only 2.0, is also in STU. The Ralliart is the 2.5L WRX competition... it would run circles around the 2.0L WRX.
I think it's a fair call. If it shows to not do well in STU, like the RX8, move it down. (Not saying moving down the RX8 to STX was the right call either... but it was moved).