Z4 e85 2007 expansion tank , oem or aftermarket ?

[Montegojones41]

Unfortunately my z4 sprung a leak and highly suspect expansion tank has given up , due to the original parts being weak or it worth looking for an improved one ie aftermarket ?
Are there any tried and tested better ones available?
If replacing is there anything else I should order at the same time
Thanks

 

[patriot66]

My original Behr OEM expansion tank split lengthways down one side about 3 years ago. I replaced it with a Meyle (2 year guarantee) tank I bought on Ebay, which has been absolutely fine

 

[enuff_zed]

I got one for my wife's 53-plate pre-facelift from Autodoc. They had a whole list of different makers so I went mid-range, for a name I knew, Hella. When it arrived, under the Hella label on the box it said Mahle??
Strangely it was cheaper than the Mahle one and the reason I went for it was because it had the sensor fitted in the bottom, whereas some apparently don't.