Ok I have a few TK 20 bords I newer used yet ,have people had issues with them in the club?
Should I update to a newer unit.
Thanks

They run fine but people are going to the newer TK40s or even better TK80s. Better driving, better sound and other features:

Now, you have a couple of decisions to make. First one is do I want sbus or regular 4 channel? If you are a wiz with radios and have no problems mapping, assigning channels, mixing, etc... then the regular PWM Tk40 or TK80 will work for you. You will still need to purchase a hobby grade radio and receiver if you do not have one.

Sbus boards are the simpler of the 2. The channels and functions are already assigned, and the radio is programmed to work following a very simple setup on an FSi6s radio. sbus uses only one wire running from board to receiver. Designation for these boards logically is TK40s and TK80s

Third, the difference between 40s and 80s boards. There isn't a lot of difference between to the 2 boards. both run using 10ch radios, both feature the same function and operating features. What you get for the $25.00 difference in price is shown in red as indicated.  

• TK80 series controller uses 8-CH conventional PWM or 10-CH  S.BUS  RC system to control R/C tank's forward/backward movement, sharp turning, pivoting, turret rotation and gun barrel evaluation at variable speed
  
  
  
  
• Ultrasonic ESC*3  for two track motor and turret rotation
  
  
  
  
• TK80 Adjustable ESC start voltage allows you to adjust lowest speed for different track motor
  
  
  
  
• Carefree reversing
  
  
  
  
• Ultra Low turn-on resistance FET for track motor ESC
  
  
  
  
• 22KHz, 8-bit high quality sound with digital sound mixer
  
  
  
  
• Maximum of 5 channel of sound track, main gun, machine gun, turret rotate, gun barrel elevation and engine sound can be generated at the same time
  
  
  
  
• TK40 3W sound output power
  
  
  
  
• TK80 On-board, CLASS-D, 15W + 15W audio amplifier with External audio input
  
  
  
  
• TK40 0.8A BEC
  
  
  
  
• TK80 2.0A BEC, can also be used to power 5.8G or WiFi FPV transmitter
  
  
  
  
• S.Bus variant (TK80S)  has EPM*4 for Left track, right track, gun elevation(EPM1) and turret rotation/gun traverses(EPM2) 
  
  
  
  
• Traditional (TK80)  variant  has EPM*4 for Left track, right track, gun elevation(EPM1) and turret rotation/gun traverses(EPM2)
  
  
  
  
• Wide operating voltage rage, from 7.2 to 12V, support  3S Li-Po battery
  
  
  
  
• Support air-soft gun with sound synchronization
  
  
  
  
• Support TAMIYA and HL IR battle unit and format
  
  
  
  
• Support RealRecoil servo port
  
  
  
  
• Support Recoil Solenoid for 2nd Machine Gun( MG2 )
  
  
  
  
• Safety shutoff prevents unwanted movement while signal lost
  
  
  
  
• Auto R/C signal detection
  
  
  
  
  
• Miniature design(92mm X 52.3mm X 20mm) for 1/25~1/16  R/C Tank
  
  
  
  
• V2 Smoker driver
  
  TK80 V2  Mixer turning is achieved by reducing track speed and also increase opposite track speed to achieve smoother turning
  
  
• TK80 Remote Volume Control
  
  
  
  
• Adjustable engine running state threshold
  
  
  
  
• Adjustable Low Battery threshold
  
  
  
  
• TK80 G2 variant support dual-axial Gun Barrel Stabilizer(GBS) with Turret and elevation sound effects
  
  
  

The K20 is at end of life from Clark and basically replaced by the TK22 series. Looks like the specs are similar to the TK22s other than programmable sound on the TK22 and not having fun elevation.
If that model is working for you and does all that you require, then I'd stick with it.
Have you got any feature you wished you have on the TK20? I know you say that you've never used them yet.

Thanks , I like the new radio but I have a 5 ch that I want to use.

I will think on my opinions. 
I want more then one working tank on battle days so I need to get more working.

Can I use a 6ch on a TK 40?

And the title is supposed to be TK 20.!
Thanks

Yes, you can use 6 ch. radio with regular TK40

You can use a 6ch with a TK-20 Series... The TK-20 only uses 4 channels (Both Sticks). Which leaves two free for anything else you want to do (Program mix to get a switch to be Engine/Cannon/etc...)

you guys are blowing my mind with all of this jargon and acronyms.  I felt like I knew what I was doing but now I'm not so sure.  I will need a lot of help and can't wait for the snow to melt and this covid crap be done and over with.