Hard Drive Replacement Kit Questions

My computer is running slow(beachballing constantly). I have upgraded to 8G of RAM, but that didn't help. Running "Etrecheck" found disk errors, so, I ran FirstAid in Disk Utilities. FirstAid says the errors are corrected, but running Etrecheck again show they are not. I am thinking about replacing the hard drive, and have several questions before I commit to the task.

First--do the HD kits listed here have complete instructions? I know the new drive will need to be formatted and partitioned, and that the old drive data will have to be transferred. Will the kit help, or, will I have to get other assistance?

Second--are there special tools that are needed? I see kits with multi-tip screwdrivers, but, I have those already. Do the kits have any other tools?

Third--what is the advantage of hybrid hard drives over standard or SSD?

I will stop there, since most of my other questions rely on what answers I get from these.

Mayer The 500GB kit is the one I was looking at. (500 GB SSD Hybrid 2.5" Hard Drive - Upgrade Kit

$104.95 Product code: IF107-098-3) I think I will just buy the drive and the SATA case. Not much difference in price, but no sense in buying what I already have.

Thanks for the help. I will probably be asking more questions when I receive the drive.