#2 You do not need to solder anything. You can take 5 cm (about two inches if you are from US) of a very thin wire, take of the insulation and put the two ends as shown here:
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fblog.zorinaq.com%2Fimages%2Fpcie-short-schematic.png&t=663&c=I1jEBZtCjVL4iQ)
You can put it directly in the PCI-E slot or in the riser. Newer motherboards will often require it to recognize the GPUs in x1 physical slots.
#3 A few people did cut their pins to insert a x16 card into a x1 slot, it works but then it becomes pretty much useless outside mining/hashing.
Happy mining.
P.S. You also don't need a x1-x16 riser, x1-x1 will suffice and it's cheaper, the only inconvenience is that you will have to cut or melt (I used a soldering gun) to get rid of the of a piece of plastic on the riser.