bottom suspension bolts

Original spec bolts really are the only answer, stainless bolts would be most unsuitable.
I have replaced my shock absorbers and springs recently, and were supplied new bolts. The bolts are not standard as they have a smaller hex head in relationship to the shank and thread size.
Also, the bolts are a very loose fit in the lower shock absorber bush. Some talk on other forums about using LE500 dog bolts, which are supposed to be a better fit. I fitted the standard bolts, at least they came out ok.
Just a couple of things to mention here....
The MG TF torque settings are on the low side for the lower suspension bolts. Torque them up to just over 100 Nm.

On the rear bolts the threaded shank of the bolt sticks out a good 15mm when tightened up. I put a nylock nut over this as to protect the thread in case I have to remove the bolt at any time. Use quality anti-seize when putting the bolts in and torque up correctly.

If you are replacing the shock absorbers, the top shock absorber nuts are a pig to get off. I had to grind three off and its a bit messy. The last one, the rear shocker by the fuel filter I used an impact gun, which after about 3 minutes of undoing and tightening, undid the nut.
I would use this method on all of the nuts.

Good luck with the work!

Sundance

Explaination of metric bolt head markings

Torque setting calculator- metric & imperial

Further to the nuts and bolts discussion... A wise old mechanical Engineer told me many yonks ago that when tightened and torqued, there should be one and a half threads showing above the nut. Seems to be mostly ignored these days. I put this to the test around the power station, and guess what: he was bob-on.

Also confusion exists in the modern world regarding the definition of a bolt: bolts have an unthreaded shank for greater tensile strength, if the thread goes to the head it's technically a screw, regardless of the head type.

There John goes again, correct on all counts, I remember, during engineering drawing lessons, being instructed to show two threads above the nut; who could argue with half a turn. And you're bloody chirpy for someone about to jump ship, or is that why you're chirpy?

John and Sue wrote: A wise old mechanical Engineer told me many yonks ago that when tightened and torqued, there should be one and a half threads showing above the nut.

Here in Oz there is a standard for structural fasteners, it is 2 threads showing above the nut.