i haven’t heard the Carreras so I can’t actually comment on them. However , others have said the Be tweeter can be very energetic even though Fritz’s implementation is also said to keep things natural and relaxed . So, I would recommend calling John and speaking to him about your room and what music you’ll be playing and how loud, etc.
He’s a super guy and will help you sort things out without giving you a hard sell.
My room is 13x18x9 with big openings on 2 of the walls.
I also agree with @chayro … you can pair them pretty effectively with a lot of amps. They are easy to drive so you could start with what you have and then upgrade the amp later.
My Carbons also sound very good with a $380 Vista Audio Spark.
At your budget, I would at least take a look at the Alstine SET120 Control amp.