best place to buy A gearbox gasket and seal kit for 06 auto Sharan

[sharan1.9]

hello again

my brother is going to rebuild my gearbox this weekend
and i need to order a full seal and gasket set for my gearbox
its a MB6 Gearbox on a 2006 Vw Sharan 1.9 Auto/Tiptronic

i just have a few questions

1.is this a part that should be on the shelf at vw
2.is there a complete gasket and seal set i can buy
3.how much should i pay
4. who are the best people to buy from

thanks