I don't see anything there that would be a benefit even over factory stuff. First off, the geometry will be way off. The MII suspension geometry was great for small cars and street rods since the beginning, but suspension technology has come a long way, especially in the past 10 years.
Second, the spindles will be very weak in comparison to dedicated truck spindles. Remember, the MII was a small car with a low center of gravity. Trucks have a very high center of gravity and put alot of stress on spindles.
Thirdly, it has "car" brakes. 11" rotors and small calipers were standard on Camaros, Chevelles, etc., but the 71-87 trucks came stock with 12" rotors and large bore calipers with gobs of clamping force. Those brakes may be an upgrade over 63-70 drums, but will never be adequate compared to factory truck brakes.
Lastly, not all coilover shocks are created equal. Just because there's a coilover "upgrade" doesn't mean it's a quality shock. Shocks have valving that can be built specifically for the application, and if the valving doesn't match the geometry, it'll create for an ill handling ride.
So basically, you'll be getting what you pay for. You may save $1000 over another brand, but it won't be near as good as it's higher priced counterparts.
I'm running the suspension from
Total Cost Involved. It's engineered for great handling with great ride quality due to being able to use a combo of specific valving and lighter spring rates. It also comes standard with 12" truck brake rotors and the bigger piston 1 ton truck calipers, or the Wilwood upgrade is available if you so choose. Yes, this may cost more than the one above, but it comes with a lifetime warranty and made with all U.S. steel.