ML350G6 Performance Server adding to RAID 5 Array

[MAHarby]

Hi

We have an HP ML350 G6 Performance Server (594874-421).

This server has the Smart Array P410i controller running 4 + 1 146GByte SAS Hot Plug drives (507125-b21) in a RAID 5 array with 1 redundant drive.

My question is, can we fit an additional 3 drives and incorporate them into the existing RAID 5 array.

Will the RAID array and the reducnant drive be OK with this ?

Will Windows 2008 R2 be OK with this ?

What is the best practise advise here for increasing the space available to the array (and subscequently the Windows partition) ?

Mark