In short, with $1000 and my equip what would you do?

I have an adcom setup that has served me well but without HDMI inputs I have to make a change.... I really only need two HDMI inputs.. Is it a crime to buy a new mid level pre-amp and keep using my adcom amps?? will this setup outperform the 870HD below? it seems like a powerhouse... What do you think of the pre-amp options below??

I use the system for movies and music and I don't really care about wifi capabilities... just sound and pushing the la scales with enough power. I'm ok going all new separates if there is a pre-amp and amp 5.1 you would recommend under $1000 total and used is fine I like ebay...

I currently have...
Adcom gtp-830 Preamp
Adcom 7500 5.1 amp 100Wpc
Klipsch la scalas and TXH klipsh rears with 15" and 12" klipsch subs

I see a GTP-870HD Adcom on ebay for $400.. Thats what got me going because I've wanted it for years and can't believe its only $400 now! its was $2500 ten years ago..

Would it be a crime to use the below pre-amps with my current adcom, are these higher performers than the 870HD above??

Outlaw 975 or Emotiva UMC-200 on ebay 300-600

Marantz AV8801 - I've read great things about "Balanced" outputs but don't know what they are or what they do? on ebay $900

Any other ideas are welcome..

Thank you!