From my experience, Skylines are just like TR's and supras. They are very capable cars if given the right improvements. They come from the factory with about 300-320 HP even though they are rated at 280.
I once heard a saying about supras that pretty much holds true for skylines. It said that supras are pretty much 500hp cars detuned to 320 for production. What that means to me is that just like TR's, add the right parts and its easy to go fast.
There are several high HP skylines and supras running around but in my experience, these were mostly tuner cars. Some company says hey, lets show off and they build a 1000 HP car, take it to a magazine so they can do an article and then it may sit for a while before being sold or they may have actually built it to race so then they go race it until they feel like showing off again.