Good Cartridge Match for a Thorens TD166 Mk II

no upgrades done to this table and am now using a Grado Blue...lots of sibilance to my ears,wondering if this is normal and due to age of 'table or cartridge itself.Original tonearm and no real need to change it.
I've used a number of vintage Thorens tables over the years.I currently own a TD 166 MK II.I've tried Ortofon OM-30 Super,LM-20,X5-MC and 2M Blue cartridges with very good to excellent results.I love the Blue and the X5-MC is my favorite(also the most expensive!).I've always used Ortofons on my Dual and Thorens tables as they often were supplied with the tables and the arms and tables were often designed and tested with Ortofon cartridges.
I still run my TD 166 MkII, all stock, which I purchased new in 1984. I've been through several pickups, older Grado, entry-level Sure, cheap Stantons. A few years ago I upgraded to an Ortofon Super OM-10. While OK sounding, I always found it a bit bright. The beauty of the OM series is the upgrade path - just change styli.

I recently posted a review of my upgrade to the OM-30 stylus in the review section:

A few weeks later and I continue to thoroughly enjoy the OM-30. I am transferring my vinyl to CD-R (for use in the car) and I am very pleased with the results! The OM series is discontinued, but you can still find NOS and sellers here on A'gon. I would expect the replacement Ortofon MM line to be at least as good as the OM series, but I can't speak from experience.

Funny you should mention sibilance, though. If the OM-30 has a weekness, it is sibilance. While not a glaring problem, it is just a little bit hotter on sibilants than I would like. It's not horrific, just a little bit of emphasis that shouldn't be there.