Replace any tweeter caps (probably 2) with Mundorf MKP's or Clarity ESA equivalents. A lot of that brightness comes from the bargain film caps they use. The Mundorf's in particular will help and bring out a lot of detail. ESA's have same detail, but less dark. This advice does not apply to the pricier Mundorfs, they go the other way.
Best,
Erik
Best,
Erik