I bought a set of airbags for the truck awhile ago. For the first week or two all seemed well. Then they leaked down, ok, I'll just check them in the morning before I head out. That lasted, well, not long. Next was keeping a foot pump on the truck as I would realize they were low on air when I hit one of the fine bridge to road transitions and would have my backbone shoved into my brain. I have had sheared mounting bolts(supplied bolts with kit that were replaced by CAT grade 8 bolts), leaks, worries that the botard at the tire place actually listens to me when I tell him not to pick the truck up on a frame lift and let the rear axle hang. Overall the bags were not horribly bad. If I had the money to spend on a compressor and gauge set up for the cab so I could monitor it then perhaps they would have been less irratating for me.
My recent tower work and associated field fire while at 160' watching my truck burn took care of one of the airbags, lines and left me sitting on the overload springs for sometime while waiting on checks. When I got my money I had a decision. Do I buy another bag and the $300-400 compressor? It will cost nearly $600 to just repair them to get them where I want. This is only for the rear, I still have to work on the front end. I looked into Timbrens once again. A little shy of $500 out the door for front and rear Timbren's. 3000#'s on the front, 6000#'s on the rear? Hmm, airbags were not rated for that. I was still heavily skeptical on their performance however and not much of a gambling man I found it hard to turn loose of the cash but caved and placed the order.
I got the Timbren's in and figured since I was extremely busy I needed to concentrate on making money and not "playing" with the truck. I wish that would have worked but reading the directions on the front Timbren's I thought, really? A prybar, a jack, block off wood and soapy water. Jack up frame of truck, prybar on original rubber bumpers, soapy water on Timbren's, place, lower frame of truck. Timbren's seated in sockets and done. I kid you not, 10-15 minutes to install these things from dragging out gear to putting it back. After that, what the heck, lets throw on the rears. Jack up frame, remove rubber bumper brackets, install Timbren's. Unfortunately the massive airbag brackets were in the way so had to remove that in order to get the bolts tight on the Timbren's. Took around 20-30 minutes for these due to complications on the hardware for the airbags, carriage bolts square block that was meant to hold it from turning stripped out so had to fight several bolts out. If you don't have airbags in the way, 15-20 minutes tops.
When I put the Timbren's on the front I immediately noticed a difference in the height of the nose, same with the rear. I was still worried about performance however and took the truck for a short test drive to my kids school to drop off waste plastic. Not a good test drive as it is relatively smooth. Over the last few days I have hauled a bunch of steel, had many horrible bridge transitions and I have to admit, I am impressed with the Timbren's. I have hit some heavy transitions on bridges but as they say, you can't fix stupid and apparently around here stupid runs amuck when it comes to transitions from road to bridge and bridge to road.
Overall you can't go wrong with either airbags or Timbren's. As far a price, what you'll pay for bags, compressor for the rear you can buy front and rear Timbren's, spend about 30 minutes installing instead of hours and have money left over to put towards your new 5" turbo back exhaust. Airbags are good except loaded like our trucks are I found that when I would air them up it would roll the weight on the front end. Softening the rear but hurting the front.
Anybody looking at Timbren's or Airbags I hope this helps. As I said, you can't go wrong with either but due to my nature I prefer the hassle free, EXTREMELY easy to install Timbren's.