Hello everyone, I recently installed a new stereo into my old mercedes and the results were ok at best. The stereo I installed is a BOSS 460RGB, bear with me here its my first time doing audio system work lol. But I wrapped the wires together correctly and covered them in electrical tape so they don't touch eachother(I know I should've soldered them but I'm not good with that and wanted to make sure it worked first.) This stereo also requires a constant 12v positive from the battery, however I'm not a fan of this so I just wired it to the 12v+ from the key switch to that so its hot in ACC or RUN not when the car is off. I wired the key switch wire together with the constant power wire and the signal wire to tell the radio to turn on. The speaker wires are all correct and were the easiest with the little sheet they give you. But when I turn the radio up on high volume, like above 23 on the knob it starts to get very staticky. But when I turn the volume knob down it smoothes out. I tried replacing the front speakers with ones out of the parts cars, which to my surprise had nice pioneer speakers in it. That didn't help and I'm stumped if its an RMS problem or just a crappy radio, or my crappy wiring job. And its a 4 channel radio and if I'm not mistaken doesn't the 240d have a 4 channel system stock? or is it dependent on the year. Also the driver side speaker cuts in and out, so if i hit a bump in the road it comes on(I know thats a wiring job problem.) Any thoughts would be helpful and I got lots of time to research this also I'm prepared to get chewed out buy the audio gurus. Just want my stereo working because I'm a young teen lol

Link to radio specs on crutchfield:
https://www.crutchfield.com/S-RsXZvt02W7B/p_104460BRGB/Boss-460BRGB-does-not-play-CDs.html