Any spacer over 5mm on a Supra requires extended studs as well. No 10mm spacer can have built in studs as 10mm isn't enough material to hold a retained stud safely for mounting a road wheel to. 25mm is big enough to be mounted as an adaptor with it's own 'extra' studs though. A 25 mm adaptor style spacer can be bolted to your original studs and have a set of its own studs, identical in size etc to the cars. If you intend using 10mm spacers, you will need new, extended studs mounted in the hubs to which they will be fitted. As above for the spigot rings though, they are designed to take up the slack in the Centre Bore of a universal fitment spacer. You can buy spacers that have been machined to be a direct fit without the need for spigot rings. One word of advice though, try and find the spigot rings in aluminium, the nylon/plastic ones tend to crumble over time and cease to do the job they were intended for, thus putting all of your forces directly to your wheel studs....this is bad!!