I'm guessing you meant OME (Old Man Emu) springs. I've heard they're great, but I'm impressed with the stock ride, that's one of the reasons I bought these trucks.
What installation woes? I've put Air Lifts in my Sienna and LC. A little over an hour, minimal tools, under $100 IIRC. I've not...
Air Lifts!
I towed a 2000 - 3000 lb trailer for my construction job for a while. With Air Lifts it was significantly more stable, and no sag at all. With more weight, you'll be glad to have a little more stability. No penalty when not towing, same smooth ride as my wife's '97 without the air...