I would look at offerings by Salk Sound, if you are considering an upgrade to speakers. Dennis Murphy's XO work is outstanding, and together, they have built some amazingly nice speakers. Reach out to Jim and have a conversation with him about what you want to achieve.
Otherwise, I agree with most of what has been said... the amp is only going to improve your system if you have speakers being starved of power. If you have low sensitivity speakers and want reference level sound, you need an amp. Absolutely. If you have High sensitivity speakers and never listen above -15dB, any old AVR can drive that.