Unable to customize a Lenovo laptop on Lenovo website?

I'm trying to buy a laptop from the Lenovo laptop (Y500) and I can't seem to customize them. When I go to the "customize and buy" screen, the system components seem to be locked, and I can't choose what I want - I can select different warranties, software, accessories and such but not hardware like hard drives, memory etc. Are Lenovo laptops available only pre-built or am I missing something obvious?

Here is where I'm buying from:
http://shop.lenovo.com/...9:0000A719

No doubt Lenovo is trying to optimize their profits, but the funny thing is that US models contain better quality components for a cheaper price!

Lenovo standardizes many products to sell a higher quality product at a lower cost. The T Series in the business line is highly customized. There are variations in the models offered on the front page and the on sale Y series Lenovo is generally the best in the industry on features for the price. They vary the sale models and some variations are purchased and re-sold by Amazon, Newegg, Tigerdirect, and many other dealers. You either wait and see if the feature you want goes on sale, or pay try to get the best price you can in shopping around at a point in time. I customized an HP and Dell to be comparable to the Y-series on sale and the price is always much higher. Lenovo Ideapads are a mass marketed item.
The variations by HP and Dell cause significant quality issues in the lack of testing or inability of the system to handle the heat involved.
http://www.pcworld.com/...ility.html
http://www.pcworld.com/..._rule.html
I highly disagree with the MacBook ratings because they don't take price into account. That is the nature of the customer base. In looking through the ratings, you find that the highest quality in consumer products have less customizing.
This is a better value with 1TB+SSD accelerate for $880 and a shorter lead time:
http://shop.lenovo.com/...:00009E58:

SLI version (Two GT 650M in crossfire), 1080p for $1050
http://www.newegg.com/...6834312439
$1150 SLI with the acceleration of the HDD and more RAM
http://www.newegg.com/...6834312440

ENVY dv6t-7300 Quad Edition series
$700.
Add GT 650M $150 > $850
Full HD $150 > $1000
1TB 5400 $50 > $1050
32GB mSSD Hard Drive Acceleration Cache $50 > $1100 (Lenovo only uses 16GB)
Lenovo is using a polymer battery that has more charge cycles
Backlit KB $20 > 1120
Bluetooth $15 > 1135
Coupon PRES100 > $1035
There are some feature differences, but they balance out.
You pay $1035 to get a comparable product to $880
Gaming:
http://www.notebookcheck.net/...849.0.html
Check out GT 650M SLI
The Y580 is GTX 660M but 1080p not on sale this week.