how different are these 2 PC?

Hi. How different are these 2 PC as i was going to buy parts but overclockers will not build it up if i brought in parts but will change certain things in the system config if i phone up. Originaly i was going to get this PC in parts.

MSI GeForce GTX 670 OC 2048MB GDDR5 PCI-Express Graphics Card

Intel Core i7-3770K 3.50GHz (Ivybridge) Socket LGA1155 Processor (77W) - Retail

Gigabyte Z77X-UD3H Intel Z77 (Socket 1155) DDR3 Motherboard (SAME)

BitFenix Shinobi XL Case

Antec High Current Pro 850W Modular '80 Plus Gold' Power Supply

Seagate Barracuda 2TB 7200RPM SATA 6Gb/s 64MB Cache - OEM

Sandisk Extreme SSD 120GB 2.5" SATA 6Gb/s Solid State Hard Drive

Microsoft Windows 7 Home Premium SP1 64-Bit - OEM

Alpenföhn K2 Mount Doom CPU Cooler (Socket LGA1156/1155/1366/AM2/AM2+/AM3/AM3+/FM1)

Corsair Vengeance Low Profile 8GB (2x4GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit

LG GH24NS90 24x DVD±RW SATA ReWriter (Black) - OEM

But as i said overclockers will not build if i buy in parts. How ever i have seen a similar PC in the system config centre in section Intel Z77 Ivybridge 10100i Configurator - Gaming System and there is a few things different like graphic card make but same power and also cpu fan and power supply. This PC is

Intel Z77 Ivybridge 10100i Configurator - Gaming System

BitFenix Shinobi XL Full Tower Gaming Case - Black

Intel Core i7 3770K 3.50GHz (Ivybridge) Socket 1155 Processor - Retail

Intel Stock Cooler (None overclocked systems)

Gigabyte Z77X-D3H Intel Z77 (Socket 1155) DDR3 Motherboard

Kingston HyperX Genesis Grey 8GB 1600MHz CAS9 Memory Kit

KFA2 GeForce GTX 670 2048MB GDDR5

Sandisk Extreme SSD 120GB SATA-3 SSD

Seagate Barracuda 7200RPM 1TB SATA 6Gb/s 64MB Cache - OEM

OcUK 22x DVD±RW SATA ReWriter (Black)

OnBoard Sound Card

OCZ ZX Series 850W PSU

Windows 7 Home Premium 64-Bit

Sharkoon 120mm 2000RPM Fan

Subtotal £1,152.24
£1,382.69 inc VAT

Just wondering how different the graphic card and fan and power supply is to the one i am going to change to?. The bottom spec is using just the overclockers system config using Intel Z77 Ivybridge 10100i Configurator - Gaming System and the top spec is buying in parts.

Thanks for any info and hope you understand the ????

Also the one i was going to buy in parts didnt have theSharkoon 120mm 2000RPM Fan so do i still need it?