looking for build parts (extended floor plate & spring)

[i8asquirrel]

I purchased a Weatherby Vanguard SA, 1x8 .308 barrel from Schillen, Varmint stock from Boyds. My favorite gunsmith has them ready for finalfinish reamer...still wiating... I saw in the Brownells catalog a extended floor plate to up nthe magazine capacity, however i saw no spring? have any of you built up a Whisper and used these? do you use the original spring? I have seen a replacement floor plate and mag assembly but its pretty pricey.......thanks for any info