Heard that newer discs (XGD3 format used by Gears 3, Space Marine and Dead Island) will be abit noisy. Me playing Gears 3 installed onto HDD still hear longer than usual noise until it turns silent.

So you should try all your discs first. If it turns out every disc got unacceptable noise level, then it's likely you got somewhat a faulty drive. But if the problem only reproduced on newer discs then it's normal. But if the noise level only persists with a particular disc then the disc itself is faulty.

So yeah, having it installed on HDD will eliminate the symptom (albeit the disc will initially spin for a moment for the security check), but not the problem (if it's in case your drive is faulty). The best way to find out is to do comparison by your ear. Pop in the same game (not the same disc) with your friend's slim (or the shop's), and hear the sound. And then try the same disc on both consoles. It's either everything's ok, your drive's faulty or your disc is. Just stating the obvious.

Unmodded
- Cheaper
- Can play online
- No headache
- Warranty covered

Playing online is the biggest thing to consider on buying an xbox360. And if you're just keen on playing older single player stuffs on the cheap, it's better to do that on PC (via Steam). Super cheap plus it's legitimate.

Lots of multiplayer-capable blockbuster games got shitty singleplayer portion lately, so there's no urge to go through modded route on the xbox. Plus the mod won't last forever, which translates to burning lots of money in the long run.