so what kind of car do you have?
for coilovers you would need some performance struts or aftermarket so that it can support the drop. Yes, coilovers are ajustable, im not really sure how you adjust those, most other ones have keys. Im pretty sure you wont need spring compressors.

As for the brand goldline, i have never heard of them and at that price it might not be the best bang for your buck. i installed my strut and springs into my accord and it took me about 9 hrs mostly by myself using hand tools. if you can get a DIY guide like me, then you should memorize the instructions like me.