Upgrading audio Lexus IS300h non Mark Levinson

Hi All,

I own a 2016 Lexus IS300h without Mark Levinson sound system.

I would like to replace the stock stereo amplifier and a couple of speakers. my question is what type of amplifier should I buy?

I want to keep all the stock audio controls. Do I need to buy a DSP amplifier? And how many channels should the amplifier be? I want to install new component speakers in the front.