Dell M4600 new owner: upgrading GPU from Quadro 1000m to AMD M4000

I recently purchased an M4600 from the Dell outlet store with an i7 2820QM processor in it (I didn't go for the 2860QM as I thought it unnecessary) for 427$ (after shipping+taxes). I've done a fair bit of browsing around doing research to see if the purchase I made was actually competitive compared to budget line laptops. Considering the build quality and CPU power, I think it mostly is (someone here point out if I'm wrong, I'm still in my return period)?

After some more research, I notice that it is possible to upgrade the GPU from its current one to an AMD M4000. I see these on Ebay for what seems to be a fairly paltry sum:
http://www.ebay.com/itm/Dell-Firepr...919?pt=LH_DefaultDomain_0&hash=item463b008a7f

So a few questions; I'm posting here since you folks seem to be quite knowledgeable about this:
1. About how big of an improvement will this give?
2. Is this the most cost efficient thing to upgrade to right now?
3. Will I need to do anything special to my laptop to install this considering it has an Nvidia in it atm? IE Bios updates, heatsinks, etc.
4. Will this turn off the ability to swap over to the integrated GPU? The integrated GPU gives a rather massive boost in battery life. I think Nvidia uses some kind of Optima thing to do it. Does AMD have its own variant?

All I can think of, thank you for any answers.

 

4. GPU switching will be disabled if you install an AMD GPU. AMD does have their own variant of this technology, but it was not supported in the Precision line until the M4800/6800.

 

I also bought a Dell M4600 from the outlet store for the same price and same specs. I think the M4600 is a great budget workstation especially at its current price. You won't find anything brand new with this build quality and specs for less than $500. I have stress tested my M4600 (i7 2820QM, 8GB ram, 1000M) and it handles everything perfectly.

1. Depends on what you use it for. Games such as Bad Company 2, CODMW2/MW3, and Source Engine-based games run great on Medium-High settings at 1080p. SolidWorks, Creo, and AutoCAD run even better. The AMD M4000 uses GDDR5 memory which is supposed to have a much higher throughput than the Quadro 1000M. If you're just doing CAD type stuff, I think the performance increase is negligible and isn't worth the upgrade. The Quadro 1000M is enough for my usage and I prefer the battery saving Optimus technology.

http://www.game-debate.com/gpu/index.php?gid=1881&gid2=984&compare=firepro-m4000-vs-quadro-k1000m

2. The best and cost efficient upgrade I think is to swap out the HDD and get an SSD. My computer runs much smoother now. You can also get a hard drive caddy to replace the DVD drive with a second hard drive. That's what I did and I'm using the second hard drive for storage.

*If you get a 7mm SSD, you will need a shim of some sort to fill in the gap because the stock HDD is 9.5mm. I used a piece of cardboard and it's working fine.

3. I believe you need to be on the latest BIOS vA16 (which you should be anyway even if you don't get the new GFX card) and you will probably need the AMD heatsink and the copper shims.