Well, I have always bought stock replacement which consist of a new water pump, and gasket. I have always been able to use my original bolts. I have had customers come in my door telling me that they have snapped their bolts in the block...so that is a common problem lately. Be carefull not to do that. If your bolts are rusty or corroded, I would replace them for sure. Clean out the holes with WD40 or PB Blaster and compressed air. Also, use anti-seeze or grease when reinstalling them. Do a T-stat and gasket, and the two little hoses that connect to the pump while you're at it.
As mentioned above, by far and away, the hardest part of replacing your waterpump is removing the old bolts and studs WITHOUT SNAPPING them off below the timing cover. Do a search on this forum for snapped waterpump bolts or accessory studs and you can read about the horror first hand. Snapping a bolt/stud will add another 4-5 hours to the job if it breaks behind the timing cover. Do yourself a favor and buy some PB Blaster and soak those bolts every chance you get. Heating the areas around the bolts with a propane torch or map gas will also help in the removal process. Whatever you do, DON'T USE AN IMPACT GUN to remove any of bolts and studs. I won't even use a breaker bar. Way too much torque. Just use a regular 3/8" ratchet and try and apply force in a "back & forth/ up & down motion. Try not to over exert too much steady pressure in any one direction. The key is slow repetitive back & forth motions. I highly recommend replacing the bolts and studs. You can buy all replacement grade 8 bolts at Lowes for short money. Here's the link for the accessory stud kit: http://www.partsamerica.com/ProductD...rtnumber=23744
Each kit only comes with one long stud, so you need to purchase two kits to get 2 of the longer studs for replacement. Use plenty of anti-seize on all bolts and studs in case you have to replace the waterpump in the future.