Final stage replacement Corsa C

Hi. The following problem. The following components are installed in my wife’s C-Corsa. HU: Sony XR-M510 with 10ner changer (my wife wants to give net;-)) FS: Axton CAC 2.6 FS-Amp: Axton C502 Sub-Amp: Axton C402 Sub: Xetec X10 Dietz Power-Cap Now I would like to exchange the two amps for one. So maybe a 4-channel with bit more power. Priced would be up to ca150€. Also used. The system should be replaced in the near future for a system with softer tweeters. i.e. only the tweeters should be exchanged. However, then 4 channels for the FS would have to come back. So maybe a 5-channel?;-) Please advise me ignorant, maybe also immediately with offers 🙂 Daaaaaanke. MfG Thomas