SSDs are what store stuff on your computer. Whenever you load something off disk, the SSD's speed is going to be what limits your speed. When you download stuff, the SSD's size determines how much you can hold. Theoretically, you could buy a hard drive instead, but they are so much slower that you should never buy one as your main drive.
Silicon Power P34A60 M.2 2280 SSD
This is about as value as you can get on an SSD. It's under half the price of many of its competitors while still being competitive on speed with some of the best. It's honestly hard to justify buying any other SSD right now.
I don't think you need anything especially fancy in a wireless card. They'll never match up to Ethernet, but I've had good experiences with cheap GIGABYTE wireless cards. Other Intel-based cards should be equivalent. The important thing I'd say is to make sure you get one with a detatched antenna to avoid interference from your metal computer case.