5100 vs 4600 series for 09 taco 4wd

hi;
this is my 3rd taco. just got off phone with bilstein rebuild hq. the guy recommended 4600 over 5100 b/c the 5100 will preload springs i think he said. i have a plain jane base model and occasionally get firewood. recently had the leaf spring upgrade. anyone who has(d) both model shocks experience? not the original shock but a real 4600.
piscator

 

I have the 4600 on the rear of my stock 2011 TRD Prerunner and am very happy with them. I had put the 4600 on the rear after having two sets of the 5100s leak. I have the 5100s up front set to 0 with the OME coils and they are great with no problems. I had the 4600 on my 99 Tacoma with an 1 1/2in AAL with no problems. For what you do they will work just fine. Hope this helps.