Advice on Rear Shock Mount + Shock DIY

[TurnAround]

Looks like either my driver's side rear shock has a defective valve, or the Rear Shock Mount is bad. Probly going to replace both. And, I'm thinking about just doing the work myself. Couple questions for you guys (Search is apparently down btw)

These are Sachs OE replacement shocks that replaced the originals at 85k. If it is indeed the shock that's bad, that means I only got 38k miles out of them (grrr..). I'm thinking I should just go with Bilstein Heavy Duty street shocks this time ($85ea from BavAuto). But I still have the 'good' replacement Sachs front struts on the car and don't want to replace them 'til they're worn out. Is that ok to mix brand designs like that (Sachs 'all gas' front, Bilstein 'combo gas/hydraulic' rear)? Downsides?

Where's the best spots to place the second jack stands under the car? First will go under the rocker panel, right next to the jack lift point. Should the second go somewhere under the metal subframe? Which spot?

The Pelican Tech article I read on doing the work says in the last step, after placing the new shock on the lower mount and bolting it in, to use the hydraulic jack underneath the control arm to jack the whole thing and the shock up into place at the top. Why? When I've replaced shocks before on my Z3s, I just extend the shock piston to full length. Is it because on an X5 that won't be quite enough to reach to the top where you bolt in the RSM? I'm mostly asking because, in addition to using Jack Stands, I usually like to leave my hydraulic jack in place so that its just one more point of protection while the car is up in the air, and I'm under it. With Pelican's advice, it sounds like I have no choice but to use the jack to raise the suspension arm/wheel/spring assembly to get the new shock to fit in. Any experience with this?

Last question; Can I just reuse the rubber boot on the new Bilstein shock? The original boot was already reused on the replacement Sachs shock I'll be taking off. Its just that.. it doesn't look like the Bilstein shock comes with a boot from Bavauto. Also not sure the stock OEM boot will even fit the Bilstein shock. Thoughts?


THanks guys!