There are a few really good guides to buying Kramer's here within eBay. They cover all the basics and then some.
What i have not seen is much about fakes. I am no expert on the Kramer brand but i have been able to save myself some woe buy researching what i am thinking about buying. VintageKramer.com is one of the best sources of info about whats real and what is not.
I really want a Kramer Beretta, now i am not really fussed if it is a American, 100 Series, Focus or Striker. Now i have almost purchased 3 so called Kramer Beretta's but the body shape did not add up. So you really need to make sure that the body shape is right and that the humbucker is slanted. Because as far as i know the 'EVH' guitar was never a production model and the pickup was not slanted. Pacers had the single non slanted pickup and there alot more expensive to buy because there US Made. Neck plates don't mean s**t as these can be changed. There are a lot of so called 80's Kramer's here on eBay and not all of them are the real deal. I see alot of EVH guitars on here that have the Kramer Logo, there good guitars but no real Kramers or only parts from a real Kramer. I love the brand and own a few now, so i am finding it a lot easy now to spot the real deal from the fakes. Not to say i have not been bitten, because i have a fake Kramer Telecaster that is not a real kramer. Kramer did make a Tele style guitar but not a dead set replica of a Fender which is what i have got. So please use the Vintage Kramer web site to guide you. Don't pay too much for an import, and remember that there will always be another chance to buy the guitar you want at the right price.
Also... There is a bit of a resurgence of interest in the brand at the moment so you who is reading this may be some one i am bidding against! Having said that, the days of really cheap Kramer buying are starting to disappear, so be prepared to spend more for that 80's slice of hair metal heaven!!!! It's killing me!!!!! lol
UPDATE 23-09-09: The Kramer Forum is another fantastic place to find info on the brand. There are some really cool people on there to help you make a good choice. I am really learning some good stuff about Kramer guitars and why they are so popular. They just don't make guitars like this any more.
UPDATE 02-10-09: Not all Strikers are made from ply!!! My understanding was that Strikers were made from ply, vintagekramer.com states that there were reports of Strikers turning up with a solid wood construction instead of ply but this was not confirmed. Well consider it confirmed! I own 4 types of Striker. The first one is what i believe is a 1984/85 white Striker 300ST with beak headstock and a non fine tuning Floyd Rose. It is made from ply with a laminate surface. The second is also a 300ST, metallic blue with the pointed non tilt headstock and single locking Floyd Rose. I might add here that the trem says Floyd Rose but looks like a Floyd Rose II. Original Floyd Rose locks at the bridge as well as the neck. Floyd Rose II locks at the neck only. I believe it is around the 1985/86 mark and is also of ply construction with laminate surface. The third is a 300HST. It is identical as the last 300ST only more heavy and supports a Floyd Rose II. This has the pointed angled back headstock and i think it was made in around 1988/89. I can not find any info on what the H stands for in HST or anything about 300HST? Illuminate me please!!!! And the fourth is a 600ST. 3 on/off/coil tap switches, single locking Floyd Rose (Again it looks like a FRII), Grey (Was Metallic Red), and non tilted pointed headstock. Made from SOLID WOOD!!! this is important because if i believe what i have read on the net, this is rare. I don't think it makes it worth much more than a ply made Striker (This is more than likely basswood or something like that), but would be a better purchase over the other. Once again i am no Kramer expert so some of my statements may be wrong hence why you should always do your own research.
My Kramers So Far:
Striker 300ST 84/85
Striker 300ST 85/86
Striker 300HST 88/89
Striker 600ST 85/86
100 Series 620 89/90