Sunpower system 3.2kw quote(add to 8kw)

Hi All, I am new to solar and already have solar installed by previous owner in NJ. It’s a 8kw system with A-series sunpower panel. It’s fully paid off and was transferred to me along with RECs(I get paid monthly $91/1000units generated)

I am looking to add another 3.2kw or more to my existing system and want to use Sunpower as it’s easy to expand in-place using same PV56 and system.

I went directly with sunpower sales to get a quote for 3.2Kw systems and he gave me U- series panel for $10,380 all cash payment. Also threw in $1000 rebate (check cut to me after install) using AAA discount. So that brings the cost of Solar effectively $2.9/watt. The installation is free for system over 3kw.

I am fairly ok with the quote and will get 30% federal credit next year.

My questions

1) does going with U-series panels not a good decision? I understand they are not as efficient as M-series but I don’t know if spending extra couple if $1000s is worth it. Do these u-series degrade faster ?

2) the sales rep said , they can plug it into sale pv56 unit, so this will look as single system rather than 2 distinct one. Is this true?

3) is mixing A-series panel(my existing 8kw) with the new U-series chase any issues?

4) lastly is my quote good or do you think I can do better?

Here is my quote