JUNK! Def. don't get a radio just for the telemetry.
I bought the DX3S w/ telemetry for my Losi buggy and couldn't ever get the RPM to set up, never used the lap counter, I did hook up the temp sensor but you get VERY inaccurate readings. So I eventually just took it off too. I was getting a good reading on my "sensor", which read I was running at 260* F, which then I was like, OK and kept on racing. Come to find out, it started shutting out and I brought it in and a guy checked with his high tech Infrared and was getting 320*, which is wayy to hot and messed the engine up. Got over heated.
So, again, TELEMETRY = USELESS
^^^^and to the above said, was it set up correctly? YES, I set it up and installed in the EXACT location the Manuel says, and got faulty readings. Bad sensor you might ask? NO, I replaced the temp sensor once and got the same readings.
Besides, with nitro comes alot of cleaning/regular maintenance, so do you really want to be pulling all that crap off every time you clean? I know just having the temp. sensor on mine was a pain every time I cleaned, I pulled the Rx tray off and which the temp. sensor had to come off every time! So I could imagine the rest of that crap