Will the Alphacool D5/XT liquid cooling kit fit in my G42 Commander Case?

[OrzechowskiC]

I feel I know the answer but i want a second opinion before I come to terms with it. I have a Thermaltake G42 Commander case that has thus far served its purpose quite well. I knew that when I bought the case, it could support a 240mm liquid cooling system. Here's my problem. The liquid cooling system I want to use is the Alphacool 240 D5/XT kit. The Radiator in that kit is a little over 240mm in length but the height is 45mm since it's their "XT" radiator. Now when I look at my case where you install the radiator, there seems to be little clearance between the roof and the motherboard. I tried measuring the distance and it barely make 45mm from what I can tell. Should I just go with their 30mm option and play safe? Here is a picture of what I'm looking at.

Secondly, is there a noticeable difference in cooling between a 30mm and 45mm thick radiator?

 

[OrzechowskiC]

Well it seems no one wants to offer advice. I'm just going to assume that it will not fit in my case and i'll have to upgrade to a full tower to accommodate the liquid cooling I want.