Any warnings w/audio upgrade?

[FellowsheepTech]

Diving into the aftermarket stereo replacement this weekend. I have a 2003 3.0i w/no Nav, no DSP. I'll be replacing w/a Kenwood DDX771 (double DIN DVD), along with SWI-RC, SLC4 level converter, Metra harness, antenna adapter, dash kit and micro bypass.

For speakers I'm going with JBL GTO608c (6.5" component) in front door/pillar, and JBL GTO628 (6.5" coax) for back doors.

I think I've read that even the non-DSP amp is frequency specific for each speaker, so expecting that it won't sound right & will have to be replaced? I've been looking at a couple of affordable (~$150ish) 5 channel amps...anything I really do or don't want to consider? I don't have one sitting here because still not clear on the need & what the level converter buys me with the OEM amp. If I can use existing and it's decent enough I save the effort of interior disassembly & cable running for new amp.

If OEM amp survives the experiment, thinking of adding slim powered sub in the future. If new amp goes in, a sub will go in with it.

I've been reading up on the forums & watching YouTube videos, and it seems like the non-DSP swap is straightforward enough. I still wonder if I'm missing something...

One thing I'm cautious about - I'm OK w/losing some OBC funtions (range, etc.) but can I lockout or screw up something else?

Appreciate any feedback...
Chris