I'd have to say the Lydian Beta. But, I have not heard the Shelter-so factor that in.
Also, I used to have a rega 25. Ditto the recommendation on the counterwieght, vta adjuster. Also, try a different matt, the ringmat helped me. Finally, change the arm cables. Spend as much as you can here.
Oh, one last thing, I put my p25 on DH cones and squares, the jumbos. Put the cones real close to the rubber feet. Tighted focus and depth quite a bit.
Good luck...
Also, I used to have a rega 25. Ditto the recommendation on the counterwieght, vta adjuster. Also, try a different matt, the ringmat helped me. Finally, change the arm cables. Spend as much as you can here.
Oh, one last thing, I put my p25 on DH cones and squares, the jumbos. Put the cones real close to the rubber feet. Tighted focus and depth quite a bit.
Good luck...