Use existing Amp or not?

[DanWEC]

Hello, will be replacing my original Porsche radio soon with a good double din. Will be replacing all 6 speakers eventually as well. It's not the Bose system, but the CDR-220 with DSP and an amp in the front.

Just wondering about the quality of that amp vs an inbuilt one in a Kenwood or Sony head unit.

So my question is, would be better to run the line-outs to the existing amp, or remove it and power everything with the head unit?

I suppose the best answer is to replace the amp with a better one, but I don't want to go too crazy with buying audio for this car. Best bang for the buck.

Thanks.

2000 Boxster S