Newbie needs advice on DIY Kit installer vs Turn key company

Backstory:
Complete beginner here wanting to go solar. I have gotten several quotes for my house and most of what i am getting is about $2 per watt and up for a 15-17kW system. So around $35k. These systems are On Grid only with Enphase ES7600 Inverters (or similar) and optimizers (some did simple string with Remote shutdown units only). I would have no ability to later add my own Lithium battery setup, connect my Generator, or do anything DIY.

I am also looking at going with a local installer and pick my own Inverter and panels and they would install panels, do electrical and permits/interconnect for $8k. So I am liking this more, if i can have my Hybrid inverter (Sol-Ark 15k or EG4 18kPV), buy panels locally on pallets, and have the installer source the racking, and optimizers (Tigo or Sol-Ark). I get a warranty from them for roof work, and they make sure it is all setup. I also get the right equipment, with the added bonus of already having a transferswitch for generator, i can add batteries, and it is all future DIY.

Right now i am trying to come up with the estimated cost of components, with the hopes of getting a close apples to apples price comparison for the above scenarios. Obviously Turn key includes everything and has final value $2 per watt. Can you help me create the list of items needed to see how much i can save, if i go with the Local installer company?

I have started an excel sheet but it is still sparce. if anyone can help suggest items or categories needed, that would be great.

If you have the money pick the $8000 quote and ask them to make it $8500 snd buy a battery now.
I wouldn’t do the $35k

$8k is the way, with caveats.
Is the local installer reputable? 8k seems cheap to me.
You become the system designer, and need to make sure you have all of the system and balance of components ready for the installer.
With the short list you have here, your material cost is over 21K.

I designed and built my own system and I think it was worth it. I went over budget and the learning curve gave me a few grey hairs.
Good luck to you.

As a June post this may be done by now. Similar position but looking at Signature's panels, 40 x 390 Canadian CS6Rs for $5,685 (pallet+10) with occasional free shipping. You have a 10 hour round trip,so a long day if your go yourself.

I'm also learning but my initial estimate had shut down switches for strings to the EG4 18, not for individual panels. Do they provide additional benefit for you? Also, have you run pvwatts calculator? That many panels puts you in the 20kW range, if needed ok but if you need 15kW then fewer panels may lessen install cost.