FM GT series, Ferrari #62 488 GTE - illegal tune?

I’ve just been racing in the GT series driving the 2019 Ferrari #62 Risi Competizione 488 GTE.
My car is BHP capped at 583 and was completely dominated by VNX PARALLEL K1.

So I saved the replay and watched it back with the telemetry open. His car which is the same as mine has 600bhp.
No matter what I do in performance if I have 600 bhp and try to load it during race practice I get a message saying “illegal tune”

Is there a way to get the Ferrari up to 600bhp without it been classed as illegal or is this some sort of glitch or is he cheating?