Everyone I know plays SR2 (I know, its what everyone has been use to for 15 years) and I just recently came across a bunch of SR3 books. Would I be able to use these SR3 books easily with SR2? How much different are the two versions? I mainly want to know about weapons/vehicles/magic in some source books. And I was also wondering if there was any way to get a copy of the second edition corebook online. I can't find anything about SR2 rules on the internet. I had it at one point from a torrent but I lost my books on the computer. I hope what I am asking isn't illegal being that the books has been out of print for years.

Magic, decking and skills are the biggest changes I think. I don't know if any of that will make SR3 modules unplayable in SR2.

Many old books are available in legally purchasable pdfs, I'm not sure if that includes the SR2 main book.

buy one on ebay or amazon they go for like 5 bucks.

I was going to say I would give you a copy that was falling apart for the cost of shipping. What good is that, you ask? You could go ahead and take it apart, scan it yourself, then take it to a place like Kinkos and have it spiral bound. Then I decided I would go ahead and scan myself an electronic copy. If you want it for shipping cost when I am finished, let me know.

Or you could win the fiction contest I'm running and get a good copy. Or I'll sell you a good copy for $5 and shipping - skip ebay.

Or. Or. You could find his address. Drive over to his house, or fly, your choice. Put a banana in his face and say "Give me the f**kin' keys you c**ksucker motherf**ker!!!"

And then leave.

I mean it's an option.

The difference between SR2 and SR3 are fairly minor. The matrix is different, but the programs all carry over, it's just the paradigm for describing the host. The skills are different, so is initiative. There are a bunch of little changes to magic (the big one being the loss of grounding and changing spell locks for sustaining foci). Again, no real loss. Beyond that, and assuming you don't mind fooling with the timeline (since SR3 equipment technically came after SR2 equipment chronologically), the two systems are almost completely interchangeable in regards to equipment, NPCs, etc. If anything, SR2 allows MORE stuff than SR3, making it easier to go from SR2 to SR3 than vice versa.

As someone else that only play sr2, I have not had any problems any modules or source books from 3rd edition.

The main changes with sr3 are the skills, initiative, dodging, metamagics, and offensive spells. Which are really easy to step backward with. Skills are pretty much almost all specializations, and in sr3 you choose the damage code, instead of having 3 different spells that have different damage codes...

ie manabolt, you decide which drain code to cast it at ... and you now resist at whatever drain code you used, instead of having to learn mana dart, mana bolt etc.

Personally I like sr2 much better, but I do like choosing the damage code on spells instead of having to learn 4 different mana spells. Everything else I would keep.

There aren't any legit sources for the sr2 pdf, there is a high quality illegal pdf out there that a friend of mine has.
You can find many sr2 books on ebay for very cheap. I got 2 sr2 main rules and 8 other books for 20 bucks.