Enjoy the drives, then if you are still game, save up for a new 15k drives. Sorry to be another nay-sayer, but SCSI and now SAS are Expensive! I plunged 5 years ago for 2 new 15k drives, and loved them for a few years, but I've fallen back into the SATA camp because I didn't want to put out 500$ everytime I wanted a new set of drives... Maybe again in the future...
The card is key, onboard hardware will make a huge difference in raid... A good card will put you back 200-300$ yikes! so yeah... play with them, but if they're not a world of improvement, don't be disappointed, just know that it does get better, and if you do decide to pony up the money, read the reviews and pick the card and drives knowing you'll pay a ridiculous amount of money for teeny tiny storage... but it's sweet, my first "new" 15k drives made my system last for 3 years or more before anything else would compete... nothing else in the last 5 years has made me say "wow" like those new 15k drives did back in the day.
Remember with SCSI cabling, if they are on the same cable, you have to number them with jumpers 0-15, the card is usually 7, so make one 0 and one 1... get the spec sheet on the manufacturer's website, and keep track of those teeny tiny jumpers because they get lost easy!
Everyone gets started with "old" SCSI drives, and gets the bug, and gets more into it... welcome! (not that I'm a spectacular member or anything, just saying that we all have done the exact same thing, and you shouldn't feel by any means different).