How do you know that the 2TG TRD oil pumps use the same alteration as the 18RG TRD ones? Have you seen this? If that's all it is, i'll just change mine.
I was told it's not a good idea to increase the strength of the spring (or what ever the spacer does) as it does increase the volume of oil, just the pressure. Now i can see this breaking out in a huge argument about "if you increase pressue, you increase the volume" saga, but it's not the case. But a little extra pressure never hurts.