General recommendation for a standard tropical community is 4x turnover, but for a heavily planted tank 10x is recommended. This doesn't all need to be filtration - you could supplement with a powerhead to just provide circulation, for example. I'd say aim for something like 1000-1200lph filtration, then add a powerhead if you want to further increase circulation.
Best suggestion on heaters is to look for fully supplied aquariums of the sort of size you want and see what wattage of heaters they supply, then up it a bit - also two slightly underpowered heaters is usually better than one, in case of failure. The Juwel Rio 240, for example, comes with a 200W heater - so I'd suggest 2 150W heaters.