$700 Used TT Upgrade Advice, Is it Worth It For Me?


Looking for some advice: I have an Audio Techinca At LP240 that has a AT 120 cartrige with new stylus and fully manual.  I am a bit of a TT newbie but like quality audio pieces. Would like to upgrade and spend about $700 for a used turntable.  Currently I have 110 wpc integrated Luxman L-509u with MM/MC selection and Revel F50 floor speakers.  I stream most of my listening via a nice DAC but like to listen to an vinyl album once a week.  Most of my vinyl is classic rock with some newer adult alternative and don't listen very loud any more. I had a little issue with rumble when playing loud but resolved it with 2 raquet balls cut in half, filled with insulation foam, sanded flat, put on audio stand,a large piece of travertine sat on the semi spheres and TT on the tile piece.  $10 DIY was very effective.

A few local listings are:
 
1 REGA PLANAR 3 TURNTABLE WITH RB-300 TONEARM, REGA ELYS 2 CARTRIDGE  $700
2 CJ Walker CJ55 turntable, Infinity Black Widow arm with  damping trough, new Cardas wire from headshell to phono plugs  $600
3 Thorens MKII TD145 turntable looks stock around $550

Would some of these selections be worth pursuing or am I already in the same league?  Also, I am not looking for a finicky TT or a project that needs to be upgraded like nice table but no tone arm.

thebman70
https://www.audionirvana.org/forum/the-audio-vault/diy/43633-rp6-hot-rodded-with-remote-motor-mount

See this link.  I did this with my RP6 and it became a phenomenal TT.  The arm change is not the biggest improvement.  It was pulling the motor off the plinth.  I only changed the arm as I broke it trying to push the envelope. Leave the arm alone.   I am confident any Rega planer with the motor remote mounted will perform at a very high level.  The Denon 103R in an aluminum head shell is a lot of cartridge for the money.  It pares very well with the arm.  The Groove Tracer parts make the package more smooth.  Less of the Rega snap and mid/high pop.  It is by no means necessary.  Pulling the motor from the plinth is a must.  
Thanks for all the suggestions.  Since Rega got so many nods, I found a P7 with a Cardis wire upgrade, stock cartridge in mint condition for $1,000.  So far I really like it!
I actually found a nitty gritty but the fluid reservoir was cracked and leaked.  I researched and used my wife's Victory Secret lotion pump (same dark color as the grity).  Cleaned it out thoroughly and inserted where the original pump was located.  Top pump handle sticks up 1.5" and only looks a little wonky and she hasn't noticed her lotion is missing yet lol.