According to my experience, DHL charged me about Rs2800 for clearing my injectors in 2017 (as you know ). All 4 injectors were $87 at that time and DHL charged me $36 to bring it to Kandy from UAE (3 days as I remember). Delcalred value was $60 and Total weight was 1Kg.
If the calculation is right, I have paid ~24% as tax. But, when I try to release other items (not vehicle parts) the tax was about 14% or something.
And intersting thing is I ordered same injectors last year from China (Genuine, Reconditioned) for another car with China post and they reached my home. Same thing for USPS; some stuffs will be stucked in customs and some will not. I don't know how they do that may be the weight of the package or the size of the package or the custom declaration or may be the carrier or may be the luck?
Same thing for electronics too including mobile phones. You don't have to be a girl, if you can talk and behave good you can get them released. If you try to cheat, it will be more problems