Question about aftermarket head unit with JBL

Hi TW,

Long time lurker, but this is my first post.

I previously owned a Subaru Crosstrek and got pretty hooked on Apple CarPlay. I spend a lot of time in messy Bay Area traffic and Waze navigation is a total life saver.

I've now got a 2019 TRD Off Road with the JBL system and I've ordered a new head unit, harness, Crux interface and adapters from Crutchfield. It seems like that should all work, but the Crutchfield site pops up this warning for my truck:

If you are bypassing the factory amp in this vehicle, we recommend replacing the low-impedance factory speakers with standard 4-ohm aftermarket speakers (or add an aftermarket amplifier) to prevent overheating and other damage to your new radio.​

Do I need to worry about this? I decided to go with the

$295 Alpine ILX-w650 7" Double DIN Touchscreen Digital Multimedia Receiver with Bluetooth, Apple CarPlay and Android Auto

Alpine ILX-w650, which has a small on-board amplifier, but I don't know anything about impedance matching or whether or not I'll damage the factory JBL stuff by not heeding Crutchfield's warning.

Eventually I'd like to replace the JBL stuff altogether but for now I just wanted something cheap that would get me CarPlay since I spend a lot of time in city traffic.

Appreciate any info in advance; TW has been a wealth of great information.