which preamp match best with Krell Evo 402 ?

I have an EVO 222 and think it's awesome coming after a ML 326s and an ARC Ref. 3. Do use an upgraded cast cable such as Tara.

I concur on the Evo222. I have one with the Evo600s and it's great, particularly in cast mode.

I see either 202 or 222 will be a nice match acording to suggetions. However, Audio research Ref 3 would be another strong candidate?

Forget the pre-amp, go direct in with a DCS Elgar DAC.
Audio nirvana!

With mediocre ones probably yes, you will be better off going direct from an Elgar Plus to amp. However, given good/excellent ones, no way, Imo running a pre-amp is still the way to go--much better.