SE

The clunking is normal. The springs are compressing a bit under full lock and the weight is transfered to the turning side of the car. I think it's called static compression/camber. The noise is easier to notice if you aren't running a lot of preload or no helper springs on coilover suspension.

For the feeling of lack of grip, this is also normal as that side of the car/tire is under static camber during compression. There will be less of a contact patch on the outside edge of the tire (or inside edge depending on which wheel you're talking about). You actually get more grip, unless your alignment is out of spec. It just feels like less grip because of the quicker turn in from the front wheels whilst the rears aren't moving as much.