You can run 30%, but with 23% oil, you should not use it with low oil, but the 175 is designed to be used with 25%, but the oil content is 18%, so in my opinion both work the same as there is really not much difference between them.

One good thing on the 175 is that is so ridiculously powerfull you can fly with even less nitro, I think the engine will outperform almost all other engines with 15% nitro. This lowers the operating cost and it has the newest upgrades in the pump and it is the easiest to set so far.

Regards