Yup, the Gabriel VSTs are the best budget shock. I also like Rancho shocks, but sometimes their RSX or 5000 shocks aren't consistent, so I'd go with their 9000, and those are a bit pricey. So save some money though you can go with 9000s up front and 5000s in the rear, that should work well, and should be around $200 for the 2 + 2 set.
Bilsteins are about 250 for a set and are very good.
IMO you should either go with the Gabriels and save some money or go ahead and expand your budget and get the others I recommended.