Is a pin fin heatsink with 4 fans enough for 2x 80W LEDs
What is the thermal resistance of the heatsink - hint usually stated in degC per watt.

I couldn't see it in the link but it might be in the order of 0.25degC per watt and if so it will warm up maybe 40 degC if all the power is converted to heat. You must find out how efficient the LEDs are - I suspect a ballpark figure of 20% and this means 128 watts are dissipated as heat.

Again if the heatsink is 0.25degC per watt then it will warm up to 32degC above ambient.

The effect of the fans could be good enough to halve or quarter this temperature rise. If you are lucky the heatsink may only rise 8degC.

I realize I've taken some guesses to to give an answer but at least the OP is aware of the process.

I'll say one more thing - the type of heatsink you've chosen is the best design I've come across for thermal heat dissipation - I've used a similar type for power transistors with 4 fans and it was awesome in getting rid of that pesky heat.