I've been confused for a while about the Whispbar. We have these for our older Honda Fit and they are truly impressive. Quiet and they do not reduce gas mileage either unlike the older Thule square bars I've used before. But I didn't realize that whispbar.com is actually a company acquired in 2010 by Yakima as a premium offering, so I've been trying to buy them and they've been out of stock.
As an aside, Yakima has a colorful corporation history (this is no Columbia Sportwear). It was founded in Yakima making handmade foot braces for canoes and kayak. In 1979, it was sold for $80K to Don Banducci and Steve Cole. The company was then sold to a VC firm Kransco. In 2001, Yakima was sold for$91M to Arcapita (a Bahrainian bank) as part of a rollup of kayak brands. In 2009, it was to  Kemflo International. a Taiwanese maker of filtration products and a supplier to Yakima (?!) owned by C.S. Lin and was run by the former head of a tool and storage cabinet company. In 2014, they hired Ryan Martin from Whirlpool to run the company. Apparently he knew the folks at Kemflo as they also supply to Whirlpool, so kind of an interesting history.
In any event, Yakima has taken the Whispbar technology and applied it to their own line with the Jetstream (which looks a lot like a Whispbar and is ultra quiet) and is a light alloy  ($195/pair) and the CoreBar ($119/pair). They also simplified their towers with StreamLine Towers. So a big rebranding of the whole system.
So a quick trip to Yakima tells you want you need with their fit system:

• Jetstream 50" (Black or Silver). Currently $199 • StreamLine part including the Baseline Towers ($199), BaseClip 156 (B15-5) and BaseClip 165 (B66-5) at $48 each. The big problem is that some parts are not available. So normally when you go to these online sites, it will redirect you to a white label micro site on Yakima.com, but look carefully when you return because if a part is out of stock, it may just not show up. This happened to me, the BaseClip 165 (BB66-5) which seems to out of stock at REI and rackwarehouse.com • Frontloader. There are lots of different bike roof mounts. The simplest is the Forklift ($159) front fork holder but it does require you remove the front and if you have disc brakes, good luck getting it all aligned again 🙂 The  Raptoraero ($149) style holds the down tube which really is a bad idea if you have a thin walled carbon fiber or aluminum bike. The most expensive Frontloader($189) holds the wheel alone so is much safer for the bike

You can normally get this for 20% off on sale at REI or pretty much regularly at rackwarehouse.com or rackattack.com. Also cashbackmonitor.com pretty regularly shows big rebates to these sites. See the REI list for what I mean note the current 20% discount that is on for these parts:

Item # Description Size Price Quantity Status Backorder?
1025910001 Yakima BaseLine Towers - Set of 4 NONE $159.19 1 Available N/A 1026040056 Yakima BaseClips - Set of 2 BC156$38.39 1 Available N/A
1026040063 Yakima BaseClips - Set of 2 BC165 $38.39 1 Out of Stock N/A 1025980002 Yakima 50" JetStream Bars - Pair NONE$155.99 1 Available N/A
7982060019 Yakima FrontLoader Upright Bike Mount NONE \$151.19 2 Available N/A