Great choice for barrel, tho may not be best for low pressure use due to the high amount of porting, but your accuracy will be dead nuts. To make the gun LP you need to get a low pressure high flowing valve and valve pin, and a good reg such as an AA vigilante or MacDev Gladiator for n2 and hpa or a palmer stab or bob long torpedo for co2. Also you will need to buy a spring kit (around $10 for 32* one) and all should fit, tho I recommend a complete one with valve springs and main springs such as the Maddman or 32* kits. The stock bolt you have now is fine and I don't think there is any aftermarket bolts that fit the 5.0/6.0 with the top pull pin for easy bolt removal. There is a new
anti-chop bolt out for spyders and you could probably ask the guy who makes them to make it pull pin compatible. Hope this helps. Also if you do go for LP I recommend getting a barrel with less porting in order to increase efficiency.
Some links you may find useful:
http://www.ottersccustoms.com
http://spyder-club.org