Good deal, but pretty sure those s10 coil will be MUCH stiffer and ride higher than what is in there now, even if unsprung height is less. those hilux coil s are a relatively low spring rate.
After all these little things are about 2600 lbs, not 3600 lbs.
That was why I was looking at MGB coils back then, they were about 2300 lbs with a nice spring rate, and lowering springs were about $69. 3.75" diameter, varying free heights and spring rates available:
breakdown here:
http://www.teglerizer.com/mgstuff/springs.htm
ANyway hope that at least gives you a back up option, and good luck.