I have two Tunze Stream 6100s in a 140G tank and have them alternating between about 40% and 60% of max output every couple seconds, which based on the ratings the 60% would be nearly max output on a 6000 (the 6000 outputs up to 7000 l/h and 6100 outputs up to 12000 l/h)
At around 80% or so mine start to kick up the sand. The flow rate sounds quite a lot but it is spread out over a much wider area than what most other pumps output. As well as being able to control the output of the 6000/6100, they come with dry run and blockage protection which the 6060/6080s do not
The Tunzes are extremely reliable and should last you a long time, so if you do decide to get the 6000s and upgrade your tank later on you can upgrade them to 6100s if needed by just changing the transformers
The streams can be attached to either the brackets that come with them or you can buy magnet holders (which i would recommend), either way they can be rotated on the mount point