What to check & tighten underneath?
 

I have to replace my brakes soon and was would like to check & tighten all the suspension and other stuff underneath whilst the car is on stands.
It's 2001 with 56,000 miles. As far as I know there is nothing that needs replacing yet.
Anyone have any good ideas of which nuts, bolts, brackets, etc to check for tightness?
Thanks.

Charmed life - S.B. and Devon !
At your miles there should be nothing to do. Suggest you start by checking all the various parts of the undertray for damage and missing bits.

There isn't a specific joint that needs to be checked, nor is there a reason anything should have came loose, except for a negligent mechanic. If you're worried, just check everything.

With most cars you actually need to tighten these types of joints with the suspension at ride-height to eliminate having the bushing pre-loaded under normal conditions that would lead to premature failure.

I'm not sure if there's any bolt or nut that really needs to be "checked" for tightness besides for something that looks out of the ordinary. I would however make an effort to get a look at your axle boots and balljoint boots for signs of cracking or rips. I would also look for leaking fluids and where they're leaking from. Not a bad time to see if your transmission mounts are starting to leak too.

I have the shop that does race support for me do a "nut & bolt" service on my Spec Boxster at least once per year where they check the torque on nearly every fastener on the entire car.

For DIY, I'd use my Bentley repair manual and go thru Section 40 Front Suspension, Section 42 Rear Suspension, Section 34 Transmission, Section 46/47 Brakes, and Section 48 Steering and make a note of the boxes that have torque values, then decide if makes sense to re-torque. In about 20 mins using some common sense, you can probably create a very reasonable list of fasteners to check along with the correct torque values.