If you read page two of this; https://www.mgfregister.org/forum/viewtopic.php?f=8&t=10757&start=20 you will acquire enough knowledge as to whether it is for you, the basics are; a more robust tank that fits easily and this low level sensor; . The VW expansion tank is like this one; Make sure that you buy one with the blue cap and preferably with the wiring plug. If buying new then make sure that the pressure is of a reputable make.The VW tank sounds interesting, in what way is it better?
And do you have a part number or precise model and model year for the part you used.
I presume (always dangerous) that you have it wired to an aftermarket buzzer or similar in the cab. Is that right or have you connected it to an existing instrument, and if so which one please?