For the price of the spacer lift with rear coils (OME) and new struts, you might as well get the full OME 3" lift with OME struts and coils. Depending on the front springs, you may still run a small spacer on the front.
Do some research on it though. I have stock suspension still but need struts soon. I'm debating just getting Billy HD's, or getting the above kit for about $850. Billy HD's are I believe approx $300 dollars alone in the US. Here in Canada they are $700. Obviously I'll be driving to the states to buy them and tires.
If I recall correctly, the spacer lift with rear springs is $350ish? Good struts are another $300-400 at least. Puts you pretty close to the OME set-up.
EDIT: Reading more into this the 3" spacer kit looks to be $310 + any options + shipping. The rear struts I would probably run are the Billy 5125's which are quoted as $200+shipping on their site. I assume you can expect the fronts to be similar.
$710+ freight is close to basic installation of the Old Man Emu set-up. Starts at 700 but I had it up to 850 for some reason.
Please do more research though. I'm very new to researching suspension for the 4-runners. It's more of something I want, and not what I need. I'll be honest, I do gravel on weekends and very mild off-roading to get to riding and camping locations only. Mostly highway miles so it's a poser thing, but I do appreciate a good ride and spacers often don't give you that. I fear a few things with a lift kit: Wanting to run larger tires (33's - 255/85/16 = sex), worse gas mileage, and wanting to off-road. Ultimately wrecking stuff costing me more money. haha.