Nope, just file a little notch around the OD of the base of the reflector. If it's so close that it needs tape then it is touching, and if it's touching the reflector isn't sitting down as far as it could, which is the whole point of using the thinner insulator!
Tnx for all the help! I am looking for the all the links now for the parts. For now cant find the right emitter 
Any help please? Dont really know my way around those sites
What sort of throw (kCd) can one expect from such a mod, djozz ? I’d really like to know.
How come those CREE XP-G2 emitters have that low lumens rate? (around 458lm) No one with higher output? Or it is just me, just to the commercials of high lumens on a flashlight 
Do I have to get a separate board, or is that it? Sorry, probably newbie questions for u guys
That number is at the max officially-supported drive current, 1.5A for the XPG2 (XML2 quoted output numbers are at 3A). Put the XPG2 on copper and feed it 4A and the output is around 900 lumens or so.
http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Discrete-Directional/XLamp-XPG2
2000 lumens on a single XML is the Chinese measurement of lumens and converts to about 600 ANSI Lumens. :bigsmile: Seriously the lumens on adds from China are ludicrous.
The XPG2 has a more narrow beam and yes less lumens, but those lumens are easier to throw since the LED itself is smaller than the XML is. I would recommend a 17mm driver such as the QLITE that many amps in an XPG2 need a good thermal path or you can cook your emitter. (We have all cooked some emitters and so will you) For a first build I recommend pushing some but not too hard. I smoked my first few builds and it was really a kick in the stomach. You can come back and change it after a couple of builds. Pretty much everything djozz said but the 4amps.
You only think you are hooked on lights right now, once you build your light you will be screwed and totally addicted. Welcome, enjoy and good luck.
XPG2 on a copper board handles direct drive from the hottest LiIo cell on the planet just fine in single cell (or multiples in parallel) lights just fine. You won't fry one unless something goes wrong, like the MCPCB comes loose from the pill or you try running it hard out of the light while not bolted down to anything.
Thanks for all the info 
yes, I believe you about the hooked think, I really enjoy moding things, just never did it to a flashlight
Can you recomend a “beginners thread” on the forum? Want to find out more about stuff I need to be aware of
AGREED. If you can find the XINTD C8 with the brass pill to solder or screw the MCPCB onto then yes. Get a FET driver and solder braid to the springs and get an omten switch. (I also fried my switch)
Solder, screws, JB Weld, or even just plain thermal grease and clamped in place by the reflector. It's all the same in light output and everything else.
There is a learning curve paved with melted parts. Search C8 build and see what you like. Don’t follow my C8 build for anything more than a laugh. I did finally get it going. Then I removed an emitter from another light and reflowed it onto the MCPCB and loved it. Then my wife left the light on un-attended, it got too hot and it cooked the XML. I replaced that one and added braid to the springs and plugged in a Samsung 25 R with a new FET driver and I melted the switch.
DBCstm has a nice build thread on 3 C8s that he built. Here
This is a great thread filled with tons of info.
That board is ok like that. Some explaining: the size of the die of the led is important for the application: if you want much light out of a led, it helps if the die is bigger, like a XM-L2 led. But if you want to get the light far out there (much throw), a big die size is not helping you, then you want the die to be bright (the illuminance is high). The big XM-L2 can not be run as bright (per surface area) as the smaller XP-G2. So for throw you use the smaller and lower output XP-G2 led, but it will reach further than the XM-L2, at the expense of the illuminated area.
This is a good read on the theory of throw, from DrJones:
Thank you all! I just got a lot of info, so have to go study it and ofcourse I will post more questions/decisions about it
Thanx!
I found a convoy c8 host, which I like. Is there any quality difference between this and the ultrafire one?
Convoy C8 comes with a textured orange-peel reflector, just what you don't want for maximum throw. It also uses a nonstandard thread for the pill so if you want to use a replacement brass pill to fit a 20mm MCPCB you're out of luck.
20mm MCPCB works much better with the wide base XR-E reflector, no grinding/filing required to clear the wires.
I ment to change the reflector, but if the ultrafire come with the xr-e one, i will just pick that host.
This one is better but out of stock for the moment. About ten bucks more but generally agreed to have better attention to detail and features. They both work fine but if you want to push hard and throw far, generally people talk about the HD2010 as the referrer emcee for how well a light can throw. Draw backs most mention is the challenge of getting the beam dialed in. Either should do you well. Search some of the reviews about the 2 C8’s and the HD2010 to see if one appeals to you more.