So thats the scene, Here's my answer to the question.

The shop he used also saw Black Betty. She was on a lift there, and her suspension was something very unusual to the mechanics there. A few were underneath looking at it like it was made by aliens. I was in the shop with them. BB wears a 2.5" Rock Krawler 3 Link long arm coil over stage 2 suspension. Pretty much top of the suspension food chain. There is only one step further to go, and that would be a coilover rear.

Shop says - coilovers are less reliable because they need to be rebuilt from time to time. And the amount he drives would require maintenence.

I say - If your coilovers need to be rebuilt, the other option of separate springs and shocks probably need to be replaced, trying to hold up that monster.
I also say - This is a guy who didnt like a 6k power mod, so he tore the trucks heart out. Rebuilding coilovers IF he got them to that point would not be as bad as him putting in a spring and shot combo, deciding he still isnt satisfied and THEN doing coilovers.

We parked the two trucks side by side for a little while and you could see BB had a considerable amount more spring, and to stabilize that spring is a remote reservoir 2.625 remote reservoir shock.

Also, the coilover is adjustable. So where you set the spring in BB with 500 lbs less nose weight, would be different from where you set Cherry Bomb.

I think any standard spring will be overmatched by the weight in that nose, a standard shock will struggle to stabilize that struggling spring.