Max McCarthy :
Im looking at this motherboard: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157451&cm_re=lga_1150_mini_itx-_-13-157-451-_-Product.
Yes its does support G3258 overclocking. In fact, all major motherboard manufacturers had confirmed that H81/87/B85/H97 chipset based motherboards support Intel G3258 overclocking, after updating the BIOS.
On H81/87/B85/H97 you can easily overclock the G3258 anywhere between 3.8-4.0Ghz
If you're looking to push beyond 4.0Ghz like somewhere around 4.4-4.7Ghz you may require a Z87/97 chipset based motherboard.
Cheers!