If you are flying something fast it does not mean you have to fly it at max speed, not sure what a Cirrus stalling speed is, but I am sure you can fly it slower, that and a bit of forward planning and you should not have too much of a problem, as far as someone blocking the r/t goes, if you have got your joining call in early enough (too many leave it until they are only a couple of mins away)then there is still no problem if you keep to the rights of way - though it can be that you may need to work a bit more at fitting in to the traffic, maybe even holding off or staying in the overhead until a suitable gap.