Placing styro under a tank with a moulded frame (which Perfecto & All-Glass tanks all have) is a waste of both time & money, and in most cases will also cause the warranty of the aquarium to be void. The key is to level the stand, not the tank.
Aquariums only need to be evenly supported (as in no twisting force) on all 4 corners. The fact that many hobbyists use styro, and/or swear by it, doesn't prove anything. Many hobbyists also swear by using eggcrate to support rocks etc, and feel that it is somehow distributing the weight of the rocks better than the glass could. It doesn't.
The original All-Glass tanks in the US were built without any plastic frame, without any kind of frame at all. European tanks are for the most part still frameless. Europeans use styro as the vast majority of their tanks do not have plastic moulded frames, and in that case using something such as styro is a very good idea. In many cases the manufacturers of those tanks (solid glass bottoms) will void the warranty if you
don't use styro under the base of the aquarium. Ditto to many larger tanks built in the USA.
So to styro or not really boils down to what style of tank one owns.
Just to prove a point that aquariums with molded frames only need to be supported evenly in each of their 4 corners ......
Andy Hudson from Central Aquatics (the owners of All-Glass aquariums) Research & Development dept. states the same thing and I have seen him set up tanks with rocks loaded to the brim, solid rocks, with no eggcrate, and no styro under the tank. Load testing to the extreme.
When in doubt, check with your aquarium manufacturer as per their set up instructions, and their warranty.