Cartridge or cable upgrade

Ditch Sumiko BP. It's cold and harsh sounding. 10x5 seems to be the right track.

I would do both really. Which one is your choice. I use the Dynavector 10x5 on my Rega and it is awesome! I have never been a fan of Monster Cable (multi stranded) Signal cable makes a silver series for a lot less money than Anti Cable and you will be amazed at the results. Or you could look at something from Morrow Audio (around $150). Nice system tho the upgrades your thinking of will really bring home the dynamics and resolution. Enjoy!

Get a new 10x5 and buy a good used pair of IC's like an AQ Jaguar for 100-150. They sound way better than anti cables and have the DBS system which is a good choice for TT's because they stay broken in with little use.

Again, agreed with both Mattmiller and Zd542,
There are many cables out there better than the antis at a more affordable price.

You all rock. Thank you for all the advice and guidance. Some further questions:

1. How thick a mat should I get if I go the Herbie Mat route?

2. Yes, the table is probably the weaker link in the system, but at this stage I'm not sure how invested I want to get in the analog side of things. However, if I do pursue it, what's a good table that would be a step up from the 5.1? Figure ~$1000 used.