just remove the items from NEI, like the NEI addon whose name i can't remember right now that removes stuff like a thpusand drums and 30 pages of microblocks.
I think that Mod is called "NEI" and has a Subset Function to disable all the unwanted Items.
Also there are far worse things than the clutter of Default GT. Imagine having GT Debug Mode on, because that shows ALL the GT Items. I have 300 Pages of NEI due to that (in default windowed MC). There is something called Search Function and it doesn't even lag (like it did in MC 1.5).