Celica is just as quick as the Arta in the twisty stuff. I'd be happy to give the Celica 374 provided it gets 10-20kg more added to it. The Celica shouldnt be made any faster overall lap time based. So any HP boost needs to be balanced by a weight gain.
I think the main reason the Celica is slow in straight line is that it can't have a stage 3 upgrade. Smething to be looked at for season 3 (a total regs overhaul now is out of the question) is stage 3 tuning. Only the Celica and rx7 don't have it and they pay. The Celica is slow, and the rx7 is shocking getting out of the corners.
But to be fair guys, the regs were announced weeks ago, we shouldn't be starting this discussion now lol, that time has been and gone.
Like Phil says, all the lap times are close, it's just how they get there. Inevitably some cars will struggle more than others when overtaking, but without making them dominant in qualifying spec there's nothing that can be done