Not sure what you mean by the 'slots'? There are the two fittings for the jack in the tool kit on the Coupe. Are there four on the Spider because of the less rigid body? Either way, I wouldn't put a trolley jack under them.
Slots is a poor term. They are the jacking points that project down from the cills and are intended for use with a scissor jack. Agree about trolley jacks.
The four square attachments with the hole in the middle are in fact fittings used on the production line to fit the body shell to it's overhead cradle. It's a risky business using them as jacking points, though many have over the years.
Well, every day's a schoolday. I never knew that. If you were to spread the load over all four attachments to raise the car completely off the ground for stuff like exhaust repairs, would that caveat still apply?
The only official points for a trolley jack are the 'plates' below the rear bumper and to the front of the sub frame, but using these doesn't get the car very high. I use the sub frame near the wishbone, or to get even higher, the rear of the sub frame from behind the front wheels. At the back I use the centre fitting point for the link arms, but extreme care is needed to keep away from the link arms themselves, as these can be flimsy, and once bent even slightly your rear suspension geometry is gone.
Yes, that mirrors my experiences. I'm aware of the fragility of the link arms. When I used the front jacking point years ago it didn't inspire me with confidence, so I've never used it since. At some point my front subframe will be coming off to be refurbished and I'm thinking of getting some plates welded on to act as jacking points. Can you see a flaw in my cunning plan?
Thanks, Stuart. I've never really trusted the front crossmember either.