Just finished detailing my wife's ES350 and here's my $0.02 on polisher. I have a Porter Cable, and a Griot's DA polisher. Porter Cable just can't handle anything bigger than a 3" pad so I have it set up to work on tight spots. The Griot's polisher is very strong, except it's not smooth and transmits a LOT of vibration to the hands.
I bought a Flex DA but never had a chance to try it out until today. The Flex is a BEAST. Every heavy pressure on setting "5" doesn't even begins to slow/bogs it down. I used an orange foam cutting pad with CG V36 and it was good enough for a "daily-driver" level detail. ALL the swirl and light scratches are GONE. There is a couple of pretty deep scratches (enough to catch with finger nail) left on the trunk and roof by the PO of the ES350, and the orange pad/Flex/V36 was enough to remove 80% of these deep scratches. To get them all out, I would have to use a heavier cutting compound, but it just wasn't worth the extra time for a daily driver...
Flex is a beast and my tool of choice. I have a flex 3401 and a PE14 and I love them.
The 3401 is direct drive, so you'll never bog it down, be sure to lubricate the valvet ring behind the backing plate.
If u think it's a beast with orange foam, get your hands on some Tufbuf wool pads or lake country foamed wool pads. ....that'll be a better bet than trying a new compound- that being said, having tried MANY compounds, I find chemical guys to perform mediocre at best (I actually have a review featured on their site). Their stuff isn't bad but isn't nearly as versatile in performance on multiple kinds of paint and the ability to both cut and finish.
If you haven't tried these I'd absolutely recommend them:
Meguiars 101: simply one of the most aggressive SMAT compounds around. Cuts HARD, especially with wool but finishes down well enough to final polish with most paints, it's also a piece of cake to work with, low dust, wipes off super easy and has a buffing cycle like a polish.
Menzerna Fg400: One of the best combos of cut and finish available. Will finish lsp ready on most paints with proper pad selection, it's a DAT compound, so properly breaking down the abrasives is important to final result. Not quiet as easy to work with as M101 but not hard by any means.
HD Adapt: SMAT adaptive compound that Cuts and finishes similarly to Fg400. You can also use this "leveling polish" to finish even softer paints as it changes character with pad selection.
I'm buying some M100 as well soon too, designed to work with wool. Super cheap. I'm interested to see how it does.