So I have my Whitebox host I built, working perfectly with the specs below. I'm feeling really limited by the amount of memory I have so I wanted to increase the ram. Two limiting factors are the current cost of 4 GB DDR2 DIMMS as well as lack of motherboard support for more than 8 GB of memory.

What I wanted to know is, if I change my motherboard, memory, and processor, leaving all other hardware the same, will it cause any issues with my ESXi installation or datastores?

I have ESXi installed on my main datastore which is on a PERC 5/i (with tape trick) via 3 WD Black 1TB HDD's in Raid 5. All VM's also share this datastore.

Current Setup
-Intel BOXDP43TF LGA 775 Intel P43 ATX Intel Motherboard
-Rosewill RP500-2 500W ATX12V v2.01 Power Supply
-Dell Perc 5/i (w/tape trick)
-G.SKILL PI Black 8GB (4 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
-4x Western Digital Caviar Black WD1001FALS 1TB 7200 RPM SATA 3.0Gb/s (3 in Raid 5 on the PERC, 1 on Motherboard controller)
-Intel E8400 C2D

Proposed Changes

-Intel BOXDP43TF LGA 775 Intel P43 ATX Intel Motherboard
-Rosewill RP500-2 500W ATX12V v2.01 Power Supply
-Dell Perc 5/i (w/tape trick)
-G.SKILL PI Black 8GB (4 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
-4x Western Digital Caviar Black WD1001FALS 1TB 7200 RPM SATA 3.0Gb/s (3 in Raid 5 on the PERC, 1 on Motherboard controller)
-Intel E8400 C2D
-GIGABYTE GA-P45T-ES3G LGA 775 Intel P45 ATX Intel Motherboard
-G.SKILL Ripjaws Series 16GB (4 x 4GB) 240-Pin DDR3 SDRAM DDR3 1066 (PC3 8500)
-Intel Q6600 C2 Quad

My question is, how should I go about making these changes? I have about 9 VM's on this host that I don't want to lose. I host Exchange and AD for my friends and family.

I haven't done this before, and I wouldn't without a backup of the VM data. Here's what I would try:

1) Setup the new system and I would include an Intel Pro 1000 card if the Gigabyte MB doesn't have one. It'll be easier than trying to add a realtek driver (I'm making assumptions on what the MB has).

2) Migrate the controller and RAID array to the new host. Set the RAID controller to be the boot device.

3) ESXi should boot, but the networking might not come up right.

4) Login to the DCUI and find the system reset option. That won't took any datastores on the array.

5) Boot up and reconfigure the host. Browse the datastore, find the VMX files for your VM, right click and select add to inventory.