Installed SPC rear camber kit after installing swift and got an alignment!

gstraw

All this chat about needing more suspension changes is really putting me off

My plan was to get Eibachs springs and 25mm spacers. I seem to be getting confused with products available so maybe someone can advise:

In the uk, we have access to Camber Bolts for the rear : Eibach Rear Camber Correction Kit - 370Z - FUNKY POWER

and we have access to Camber kit for the rear (Which seems to come with the bolts linked above) :
350z SPC Rear Adjustable Camber Arm | Tarmac Sportz

then we also have the front camber arms: Eibach Front Camber Correction Kit - 370Z - FUNKY POWER

Now, can somone please advise why anyone would get the rear camber arms if the rear camber bolts can do the 'same adjustment'? both items say they can do +- 3 degrees of camber.

lastly, what is the normal camber adjustment on the stock camber bolts? if its something like +- 2 degrees, then these bolts (the 1st link) would provide an additional 1 degrees of adjustment?

im keen to learn from people who also have this eibach setup and what they done to get the camber back since this seems to be a very subjective area. Fund are low so if loweing turns out to be too expensive, i'll just wack on some eibach 25mm spacers and not lower although my amuse kit may look odd on a non lowered car.

thanks