I've got the Rosso and the Revell 512 TR in my stach and after carefull examination I think I prefer the Rosso.
Although it does not have a complete engine, just a simplified one.
The body has a lower, more sportscar-like stance. It is less bulky than the Revellogram offering.
I do not know who's got the dimensions more right but I'm guessing Rosso.
The 512 TR has a more rounded appearance than the Testarossa and I feel Rosso captured that better.
Rosso's mainly has seperate vents, which saves a lot of time masking, the wheels definately look better, so do the tires.
I'm not aware of any fitment issues withe the Rosso 512 TR but I haven't built it yet, Revellograms however has a bad reputation and as mentioned before, it's really a Testarossa withe a 512 TR body on it.
On the plus side: Revell has reissued theirs in a very appealing new box, unfortunately it is not a new tooling but easily available...