Pretty much whats been said above
Would go with Dave and use 2500 (or similar) even on a new car........ the filler heavy products and any so called 'easy clean' / 'protective' type products the dealer will have used want to come off.....
As Dave says, use a panel wipe or IPA mix to remove and residues after polishing and before any further applications of products....... agree with Scott about the use of a glaze but use the IPA/panel wipes to remove residue and not the glaze....
a glaze coat will really enhance the depth/ wet look, although if you work through the stages of the polish and refine correctly, you can jewel the paint without it but you'll be adding multiple passes..
Go for a sealent and wax combination, sealent always first....... and use products that give you the finish you like......
Although the 3-1 product in the thread is Menzerna and WILL give good results, IMO steer clear of any 3-1 type products! A 'cut' will break down at a different rate than a 'polish' and a 'cut'/'polish' will remove wax
Hence why different products require different techniques/ speeds etc etc to fully break down.........