Waterway Power Defender 140/165 questions

Hey there… I’m shopping out a couple of your recommended pumps… the Power Defender 140 and 165. Currently I have a single speed 3/4HP pump and want to put in a variable speed. I have 1.5" piping everywhere. My TDH is 41ft. I am thinking that either of these would suit my needs (would they?) but I have a few questions:

  1. I plan to self-install. Will the manufacturers warranty still apply? Part of my rationale for these pumps was to avoid Pentair (and presumably Hayward) since they apparently have become anti-DIY with their restrictive warranties.

  2. The PD 165… does it support 1.5 and 2" plumbing?

  3. Is there any benefit to buying the bigger pump? It seems like the smaller one would suffice flow-wise, but would it be worth the extra expense for the 165?

  4. Are these quiet pumps?

Thanks!