Mcintosh MC240 + Audio Research SP-8?

I operate Dynaudio Evidence Temptation with Mcintosh MC240 power amp and Audio Research SP-8 preamp.

Any good suggestion to upgrade the sound?
What aspect of your system's present sound are your trying to 'improve'. And, for those of us not intimately familar with your speakers, what is their nominal impedence, minimum impedence, and what is their efficiency spec? What in your budget for this 'improvement'?
Specifications from Stereophile review,

And Captain Kirk said, “Scotty, we need more power!”
Newbee makes a very good point. If the choice was mine to make, I would definitely go with a new preamp. But thats just me.
That MC240 is from the 1960s and is probably worth more than you paid for it. Original retail was $288.00! They sell for over $2k now, which is fine for collectors but is not for someone looking for best sound.
The SP-8 is probably a better bet sonically, revered for its sound quality more than its collectability.
If you've got the model right, those Dynaudio speakers retailed for $30k and deserve better electronics. Go find a Dynaudio dealer near you to get a better idea of what you should do. IMHO, do not buy replacement electronics without listening to them first!
Thank you, everyone.

I upgraded speakers into Dynaudio Temptation nowadays. But still as you mentioned, Amps are old versions in 1960s and 1980s.

I don't know how promising Temptations are and what kind amplifiers users have for making sound with Temptations.

Just my preferred sound was not vintage stuffs so I gave up Altec A5 systems. I have used Altec only for 2 months.

Now, I have Totem Mani 2 signature as well and I like them much. But I want warmer sound than MANI does now. Mani has good resolution, huge soundstage, detail sound image and deep bass. I liked it!!
But warmer and fainty sound of high frequency I expect for Temptation.

1. Tube or TR
2. I keep the preamp, AR SP-8?
3. If i choose Krell 400cx, ovrhaul needed? (produced 10 year ago)
4. Reference combination? (10 years passed since Temptation were produced. So, I believe some references.

If the SP-8 has not been recapped in 15 yrs. or more, it would be a good idea to do that. It will improve the sound of the preamp.