Pls help me decide Pass Labs X250.8 or Luxman M900u

Are there other amp's you think I should look at?  I understand the Pass XA's are warmer (but also with less dynamic bass).  I think the D4 series overall is less bright that the D3 series and I like the Top End sound already with my 803's from the X5, but I know it can get significantly better.

@yoyoyaya thank for the response , @audphile1  you make a very good point.

what specs do I need to look at to understand if the Backert Rhumba Extreme 1.4 would pair well with a Pass Labs X250.8 ?

https://backertlabs.com/tube-bias-adjusted-automatically/

https://backertlabs.com/more-goodies/

@audphile1

So, I found this on the Backert

Input impedance: 34,000Ω
Output impedance: Below 80Ω

On the Pass Labs X250.8 specs

So thoughts? Input 100,000 on amp

output on Pre 80ohms so looks good?

I really appreciate all of the responses here!

I’ll update once I make my purchase and have the amp in my system. Will start to focus more on the Preamp now.

The Backert Rhumba Extreme really interests me- unless I can find a used VAC Signature MkII SE

@soix I have 803D4’s (not D3’s) but you are correct about the upper registers. I’d like as much imaging, 3dimensionality and life like presentation as possible. I find magic in the small details and how notes can hang in the air.

@audphile1 I would consider a Ref6 SE but (maybe because of my lack of knowledge) thought it would be best to buy a pre amp which has Home Theater Bypass as 60% of the time the system is used for that.

You can turn the Backert off for HT , also it’s much more affordable than the VAC. Have not found a store that had both so I can so listen side by side. 

@audphile1 what is the input on the Ref 6 labeled, as I have been looking at the back panels and only see Bal 1-4 and SE 1-4 inputs.

Thanks again for all your great info!