Ideally you should have the oil temps close to the water temp again this will be effected by fitted oil coolers and power output etc on different cars.
have to say that 100 seems a bit high for cruising but i have found the factory gauge to not be all the acurate. still 100 is not damaging the oil i believe mineral based oil starts to break down around 125 again depending on the quality of the oil. But again 90 is better than 100, how dark is the oil when changed?
I may be wrong but oil pumps are positive displacement gear pumps so really shouldnt be an issue with a standard pump or after market, unless there is to much restriction in the cooler you use, resulting in oil pressure drop. and thats a bad bad thing!
I run 3 coolers on a standard pump ( well i think it is ) and had no issues yet, long may it continue.