I had OME on my '99 Taco and thought it was the best thing ever.
I bought my T4R at the beginning of January and thought I was going to go OME all the way until I started researching it here and in other forums.
I ended up buying the toytec/bilstein kit and I have not regretted it at all.
3" Lift W/ Bilstein 5100 Height Adj Coilovers FJ/4Runner
Install was fairly easy with another person—complete suspension with UCAs installed in around 4 hours with a lunch break.
Her first trip was several hundred miles north up the west coast to see the redwoods meet the ocean so the lady (a little uncomfortable at the speeds) and I could take her down fire trails that were mashed between huge redwood trees. I still have my stock tires, etc. and it drove so much better than the stock suspension.
I ended up purchasing the LR UCAs at the same time to save my CVs from extra wear and because I want to upgrade the tires soon.
In total I paid about $50 cheaper than the site you posted with the code and without the diff drop. My shipping to CA was around $80 from Toytec.