Price guide Australia 265/35/18 Kumho Esta 712 @ $190 each brand new. 5/5/2006, Purchased the same tyres in 2009 for $195 each.
http://www.kumho.com.au/ made in Korea :-) ( Scary in WET, do not go over 3000 rpm - OK for straight dry summber days. )
If you ever happen to take you wheels off and the nuts seize. You can always change it and its easy and cheaper then you think.
Snapped stud in lug nut , snapped studs and rounded stud.
If you are farmiliar with cares and are focused and have all the tools handy - it should take only 2 hrs max.
Take off your tyres, then your rear brake, then the disk. The disk might be stuck, but you just have to give it a good hit with a hammer to losen it. Make sure that you have the car on a level surface ( very important) as the hand brakes need to be off or else you wont be able to take the brakes off. Stop car from moving by putting something to stop the car from moving. Bricks on the front wills front two wheels on either side will do.
Because you have to rotate the wheels to line up with the gap so that you can remove the broken studs. Hence both rear wheels need to be jacked up, another jack for the rear will do, or you can put them on car stands.
Once you have lined the stud up with the gap behind you can hit it, so that it pops out, you may need a bit of force. Putting the studs in, you have to use this gap to get the new studs in also.
You can get the parts from any most spare parts, Part number NS457 - Price guide is about $4 each stud. I can confirm that these fit on the rears of my R33 S1 GTsT.
To install the wheel studs, line it up in the gap and use some washers and then tighten it up. Make sure that you have lined it up straight or else it wont fit, it doesnt hurt to put some grease and WD40. Then just tighten the nut until it pulls the stud into place. ( Drop the other rear wheel so that it has traction, making it easier to tighten )
Once all studs and back in, just put your disk, brakes and tyres back on. Just a tip that I got - putting a bit of grease on the studs stops the studs from flaking and helps stop the nuts from seizing up.