Need some help with my suspension.

So I just purchased my truck and the owner claimed it has a "towing package"
Now, at first I just thought it had a simple towing hitch installed, but after looking at the suspension it seemed a little bit beefier.
Has anyone ever seen this? It seems a little different than what I have seen online.

https://66.media.tumblr.com/feefa1d0b94af421dffc299309a2ab4f/tumblr_odj8mgN6k71s3i5vvo1_1280.jpg

https://66.media.tumblr.com/ea1170949398613c78b018f1ca0bc395/tumblr_odj8mgN6k71s3i5vvo2_540.jpg

Is this oem? There's also an electronic brake proportioning valve inside the cabin that can be adjusted with a little black box.

The way it is, can I shove some 3" blocks in there to lower it a bit?
Thanks.

The suspension looks stock to me, except for the overload springs(the ones with the funny brackets). As far as I know, there was no towing package available from Mazda.
Your hitch is aftermarket. The gadget inside is an adjustable trailer brake, for electric brake equipped trailers.
Lowering 3 inches wouldn't be a problem, but removing the overload spring and the helper spring(thickest one on the bottom) will be easier to do when you install the blocks. Otherwise doing the work twice is a real killjoy.

So you're saying the safest leafs to remove are the one all the way to the bottom, and the one all the way to the top?

This is my first truck, I have two Miatas and lowering is so simple with coilovers! Lol!

And as for the front you just loosen the vertical bolt on the torsion bar, which is close to the middle of the truck?

Thank you so much.

Yes, for the rear.
Also yes for the front, BUT... if you go too low, you run the risk of dragging the adjuster on the ground. If this is what you run into, then you'll have to re-index the torsion bar. Run a search for re-indexing.