Some guidance on motors and spindle

So recently revamped my garage and in the process wanted to update my Xcarve. I was reading about the VFD spindles and was looking at my options (any advice would be appreciated 800 watt, 1.5 or 2kw). I did a lot of searching but sometimes the topics get a little off course. I found the Cncfornewbies Z axis and I am going to purchase it soon. But then I saw the option for the 269 oz motors. And on that site it’s 50.00 for one and there is a 3 pack on Amazon for 79.00. Any difference, do I even need them? I have the upgraded xcarve with the x controller. I was also trying to find the Y axis stiffeners but the site no longer works. I’m a hobbyist looking to try harder projects and bigger products. So looking to better it and prep it for a stronger spindle. Thanks I’m advance for all your help