https://www.amazon.com/Profile-Designs-Airstryke-Clip-Black/dp/B000R45OK0
These are what I use. They're very firm and very comfortable even with the pads adjusted closer together for a more aero position.
I did insert a small piece of tube/rubber under the hinges, otherwise they rattle a bit on the road.
I've put ~500mi through mine and at this point I forget they're even an add-on they feel so natural.
$160 is silly, though. You'll probably end up selling them for $50 down the line if you pick up a TT bike. Do not hesitate to grab a used pair for less.
Side note: IMLP 70.3 your first? I'm on the fence about jumping into a 70.3 as my run is still very weak but LP is going to be my first.
Keep the elevation map in mind and save your gas for the last 10 miles. This is a pretty good course for a road bike, those aero bars might not end up seeing much use.