If you are confident that you can always find a place to lock your bike in a bike rack then you might want to consider a Sold Secure Gold mini u-lock. But if you feel you might need more options, then a standard sized u-lock is a better choice.
And for me, the Granit X Plus 540 is the best all round portable bike lock available today. So if the Evolution New-U is just a little too heavy, and the extra cost is not a significant issue, this could be the best lock for you.
Hellow on kryptonite site it says kryptonite series 2 is also made with MAX-Performance, hardened steel is this a upgrade of this model?
So 13 mm of MAX-Performance, hardened steel so series 2 is exactly like the evolution mini 5
A cordless grinder will take 3-4 minutes and create lots of noise. A hydraulic cutter is silent and after some pumps it will snap. If the thieves want your bike, they will find a way to take it. So whats a detterrant, an ugly bicycle that looks cheap for starters, maybe a movement alarm, cell phone alerts. Also remember to properly lock your bike up!