RAM: Dell versus Crucial - Urgent help needed

I realise that this must have been asked before. I've performed a search (quite possibly inadequate) and can't find a thing. I also apologise in advance for the naivete of this question.

The problem

I'm just about to buy an XPS 17. To upgrade from 3GB of RAM to 4GB costs at Dell £40 ($62). This seems very expensive. From Crucial, for around the same price, I can purchase 8GB of RAM. It seems like a no-brainer, but are there any pitfalls I am missing here? How if at all will it affect the three year Dell warranty I am purchasing especially in terms of opening up the laptop?

The help is urgently required because I have a coupon that is time limited and it's about to run out.

 

Any CRU (Customer Replaceable Units, aka RAM, HDD) if changing aftermarket, Dell obviously will not cover under warranty. If by chance you ship it out for repair and it was the part you changed out that is causing the issue, Dell may charge you an out of warranty labor rate.

 

It generally makes dollars and sense to buy Dell machines with the minimum possible memory and add aftermarket memory later.

Bear in mind that if Dell factory memory fails, Dell will send you new DIMMs after you run a diag program on your laptop and report the results. If you have aftermarket memory, you'll generally have to request an RMA from the manufacturer (not the vendor, e.g. Newegg), return the DIMMS to the manufacturer, and wait for them to ship you new memory.

Brand name memory is generally reliable, but I have just been through the RMA process with Kingston at work, and Patriot for my L702x. With Patriot, I created the support ticket on Sept 12, and received an RMA and mailed off the DIMM within a couple days. Replacement memory was received Oct 6.

Even so, I would still go with aftermarket RAM for my home machines. At work where I support 60+ desktops and laptops and there's a higher expectation of 24/7 uptime, I buy Dell machines with factory RAM.

 

Thanks very much for everyone's assistance with a particular tip of the hat to mpalandr. I love a balanced and well argued case.

Eventually, I decided to go with an i5-2540M processor 2.60 with Turbo Boost etc. and 6 GBs of RAM instead of the i3-2310M processor 2.10 GHzw with 3/4 GBs of RAM so the whole Crucial thing wasn't an issue after all. I'm sure, however, that this little thread will prove useful in the future.