Any method can be made to work. Unlike some others, I choose to not hate some of them. Coils, leafs, and bags all have their place. Going lower does have its drawbacks if it is a static (always low) drop. Air gives you the option of raising up the car when necessary. Nicer ride too.
Avoid Airbagit and Helix (the Hoffman Group) like the plague. Good deals can be had at: http://thorbros.com/front_page For ultimate control, AccuAir is the way to go: http://accuairsuspension.com/ You will need a 4-link in the rear (I recommend a triangulated one), and a modern-'ish rear axle, at least. Front suspension is up to you. We just did two '41 Chevy's, one with with bags, and one with hydraulics. Both ride like a dream, but the bagged car is a nicer ride. Oh, and save some grief. Whatever you choose, from whomever, if it has pipe threads, use this: http://www.amazon.com/Thread-Sealant-Controlled-Strength-37396/dp/B0002KKTGS Loctite 565. The stuff will seal fittings with even the most mis-cut threads.
My buddy bagged his full fendered '34 Ford Coupe. After several years of fiddling with it, he removed the air bags and installed coilovers. He said if he set the air for a good ride, he'd bottom out on dips on the freeway. If he set it so it wouldn't bottom out, it rode too harsh. A friend of mine, the owner of "Hot Rods and Hobbies", has a '56 Chevy p/u. The suspension uses coilovers but the upper mounting points are adjustable using electronically controlled jack screws. That way, he can "lay frame".
Exactly. A properly designed, engineered, fabricated, and installed system will ride like nobody's business.
My 57 has bags all around. I love the ride. Getting it right makes all the difference in the world. Air ride technology system. sleeves in the back with four link and bags on the front, stock a arms.
My Studee rides in the old style, cut front coils, and de-arched, reversed eye springs in the rear. Has an excellent ride (compared to my '55 Chevy with cut coils). However, I would like to install air bags. Not to lower it, but to raise it in the front, to get over those pesky obnoxious speed bumps. .
Go bags and let me explain why.....Lowering a car and rolling low all the time is a huge commitment. When I ride my truck low there are a lot of places I can not go....speed bumps, drive ways, etc. bags may not be traditional but it gives you more freedom in my opinion...I'm sure either way you go has ups and downs. Good luck