.
Everyone loves a GB and to save fifty squid or whatever a discount is, but if there's not the opportunity I'd still recommend buying one. If you obviously like it enough to seek a GB, once you've bought one you'll quickly forget what you might have saved from the cost or even how much you paid for it. This applies to most aftermarket mods.
Also, if (unlike me) you're likely to sell it separately when you sell your car then you'll probably sell a Twintake very easily and get a fair price I reckon.