Duora 10 vs Auraspeed 90K

I'm guessing what you're looking for is not a more powerful racket, but a racket that grants you easier access to power because D10 definitely doesn't lack any power. Duora 10 is not an easy racket to use, most people probably find it difficult to generate power consistently with it.
For me 3U Auraspeed 90k is easier to generate power with compared to a 3U D10, a faster frame with the same head size. 90k also has a more repulsive frame making shuttles leave the string bed in the shorter time, this makes the 90k has a slight advantage for shots where there's little time for back swing. But this also means that a faster swing is needed for power smashes from the backcourt.
On the subject of tension limit, there's two aspect, first is the tension that manufacture would cover the warranty should the racket broke, second is the tension that the racket can take before its frame give in and sink. What you're concerned with is the first aspect, each country has different policy depending on their distributor, some distributors are reasonable while some are thrash. Ask the shop that sold you the racket what are the factors that would cause the supplier to consider the broken racket as void of warranty. If the shop tells you to just follow the recommended max tension then you should just follow the recommendation, OR you exceed the recommended tension fully understanding that the supplier would consider it as void of warranty. If you're concerned with sinking frame at high tension I'd recommend getting a LiNing racket as Yonex and Victor are more prone to this issue. Victor in particular are garbage with their recommended max tension, my 4U Jetspeed 12 with recommended max tension of 29lbs can't even take my low 24-25lbs and sank. My 3U 90K is taking 26lbs well but I don't how it would do at higher tension so consider yourself warned.
So yea, that's my two cents.