Newbie questions

Just got a 2005 f430 and had some questions
1. I have P zero tires. Do you run the tire pressure at factory pressure or other? I've always done factory settings despite tire brands on my other cars.
2. What oil do you guys like. I've always been a mobile 1 user. I live in the Atlanta area.
3. The previous owner replaced the head unit to an Alpine CDE-193BT unit. I have the speakers in the center console back which I believe are 2 subwoofers? I am not sure what sound should come out, but at any volume I hear the music at an extremely low volume. Using the front to rear fader and setting it to the rear I get no change. Turning up the volume I don't seem to get any difference. It seems I would get some difference out of the subwoofers on the base end. Any ideas?
4. It has the sticky button syndrom. For those not doing the fix, How do you clean the buttons normally? It seems the stickieness would get lots of dirt stuck to it. Just use water?
5. Has anyone installed skid plates in the front like these?

https://www.ricambiamerica.com/skd-430-pe-f430-skid-plates-in-polyethylene.html

Did they help?

6. I bought this battery tender at costco. Does anyone see any issues with it?
https://www.costco.com/Battery-Tender-Power-Plus-3-Amp-Charger.product.100241973.html

Thanks everyone