When I had my '00 Bravada and the PPIII, the 87 tune had a bit of detonation at odd times (ie. not always at WOT). I would have to run it on 89 to have the detonation go away. The Premium tune was good though with the 93 octane fuel available around me. I didn't think that the difference made it worth using the premium tune as the 87 tune with 89 octane fuel was a decent boost. I never did any long term testing though. All seat of the pants and data logging through my autoenginuity scan tool.

I liked the Hypertech for it's transmission shift algorithm changes.

 

I had the same questions too. Here's what I've done so far.
K&N filter
high flow cat
Gibson cat back system

It sounds great but I need more pick up. It will jump and squeel the tires and I have to be careful when punching it.

 

Supercharge it then if you are looking for more power. Powerdyne makes a Supercharger for your truck.

 

You will get the same results you will get with turboing it if you don't forge the guts... A blown engine. A 350 swap really wouldn't be a bad investment if cheap horsepower is the name of the game.

 

wow nobody suggested headers???????

 

I have a 97 sonoma with the 4.3 Hypertec added a lot of HP and uses regular gas. First of all which 4.3 do you have there are two one is with the vortec heads and regular intake and the other is vortec heads and vortec intake. The difference between the two is one is a 4 bolt intake and that is a vortec intake and the other is a 8 bolt. Headers, exaust, cleaning the mas ( mass air flow senser) I used break clean to clean mine out. The type of oil that you use helps I use amsoil make sure you use it in the frount and rear on 4X4's. My 4.3 runs at about 210 hp its a pickup want a be but the tires brake if i want them to. This is just a start I have a engine builder for marine engines that is going to be letting me know what else can be done. Will post that later.

 

by the way I have realized that I said 4 bolts that is 4 bolts inside the outer 4 there are two intakes they are really 8 and 12 bolt