Just about any lowering spring on the market seems to be around the same range and most people seem happy with the handling.
M&S Storm drop the same amount as the Eibach Pro Kit 1.4" front & 1.2" in the rear. The major difference between them is M&S is a linear spring opposed to Eibach's progressive spring. I'm leaning towards the Eibachs myself but I think both won't disappoint you.
They use the same logo and box as the Storm lowering springs from Korea that I bought from K8 Stinger Store. I think they are just rebranded storm lowering springs that have a larger drop and a higher spring rate. Same exact sticker on the springs just with the different logo and colors.
Just for comparison sake, the Ark springs are considered like stock and have a 3.2kg/mm front rate and a 4.9-5.8kg/mm rear. The M&S are 3.03 kg/mm front and 7.11 kg/mm rear. So a touch softer in the front and stiffer in the rear, which seems like a good match since the rear is super soft and floaty stock.
I think a progressive spring rate works better with the Stingers soft dampers and better replicates the stock system. Just my 2 cents.
You can see the box in the background, and the stickers. Look familiar? It does say on the M&S website, on the stinger 3.3 page with the picture of the springs that they are progressive.