Any trick to replacing the struts on a 90?

there is a good chance that replacing the struts won't fix the problem. They don't support any weight....
but anyway, take off the front wheels, move the calipers to the side. put a jack under the control arm to make sure it doesn't drop down. Then, get a big ass breaker bar with a pipe on the end, and take the huge bolts out of the lower strut mount. They were torqued to 150-180ft*lbs from the fractory, and probably have not moved in 13 years. Then, you have to get the upper strut nut off. An impact wrench should make it easy... otherwise, it is difficult to keep things from rotating. Then, reverse the process. Take off all the bushings and covers, and put them back on the new strut the way they came off. Be sure that you don't bung up the metal rod, or the seals in the new strut will go out.

I found it easier to get the bolts holding the strut to the spindle off by heating them with a propane torch and then impacting them off.

There's a chance your spring might be broken. And once you have the struts off, you can get the springs right out. Pretty easy.