The phrase "are far more stringent" is correct and usable in written English.
It can be used when comparing the strictness or severity of two or more things, indicating that one is significantly stricter than the other(s).
Example: "The new regulations are far more stringent than the previous ones, ensuring better compliance."
Alternatives: "are significantly stricter" or "are much more rigorous."
The tests they carry out on tap water are far more stringent.
This would be ruled out under the new proposals, which are far more stringent than have been the postwar norm.
These new laws are far more stringent than any affecting such expenditures under state or federal law.
The terms are far more stringent than those imposed on most cooperating defendants in major white-collar fraud cases, the prosecutors noted in their proposal.
The new controls are far more stringent than this Government, with its umbilical links to the gun lobby, would ever have countenanced but for the nationwide anger over the massacre of 16 Dunblane children and their teacher in March.
Needless to say, these rules are far more stringent than anything applying to sportsmen and women, who may be paid and who may bring a technical or support team of any size with them.
Their version of ending welfare was far more stringent than Mr. Clinton's.
Among the issues that would have to be worked out is drug testing, which is far more stringent on the Olympic level than on the major league level.
The terms were far more stringent than those imposed on most cooperating defendants in major white-collar fraud cases, the prosecutors said in their proposal to Judge Sullivan.
He said that he could not predict the final outcome, but that the standard would be far more stringent than 50 parts per billion.
If he makes it over the English border, he will find himself on safer ground – the Scottish interpretation of a breach of the peace charge has been far more stringent than its English counterpart.
