Hi, I’m looking for advice on suspension options.

I live in rural Costa Rica, and I know very little about cars and car maintenance.

I purchased a Year 2000 diesel 4Runner SR5 just over 1 year ago (with 132,000 miles, plus 8,000 since). No special modifications that I am aware of. It seems to me that I am having lots of problems with the suspension. Work has been done on the suspension 4 times (descriptions may seem odd, as I had to translate from Spanish):
After purchase/inspection: change stabilizer bar pins joints - front & rear
Maint #2: change 5 bushings, stabilizing rubbers and rack joint
Maint #3: remove forktail, change: bushings, rubber rack, 4 compensation structures and 4 rubbers of tensile bars
Maint #4: change: 2 bushings, stabilization rubbers, cross bar and mountings

total cost of suspension work parts and labour = $1,250

I am considering replacing the suspension system, for something more durable and reliable for the driving I do.

I drive daily on very rough (i.e. fun) roads, plus some highway driving (rarely over 40mph). I sometimes need to carry bags of dirt, etc. in the back (I try to limit this to about 350 lbs), and sometimes tow a small trailer. I’d rather not “lift” the vehicle, but would if necessary.

Does the maintenance that I have needed seem reasonable? What changes would people recommend to make the suspension more reliable? I may not be able to get the same brand names in Costa Rica, so are there particular things I should be looking for? It would help a lot if you could explain any technical terms, as i don’t have much experience with cars. Thanks!