What do you think of the K9 Thunder Self-propelled howitzer? If it goes against the XM2001 Crusader, which would win.
Link: http://en.wikipedia.org/wiki/K-9_howitzer

For those experienced in howitzers and tanks (which greatly resembles today's modern self-propelled howitzer), what do you think?

I think you should do some more research first.
The K-9 SPH is no doubt a great piece of machinery but why are you making references to tanks?
It's good. I know some folks who crewed the K-9 and they don't have any major complaints.

Well, nowadays, the self-propelled howitzers are now greatly resembling tanks

The XM2001 Crusader was replace by the XM1203 NLOS-C.

The K9 Thunder is comparable to the M109 Paladin.

Actually no.
South Korea fields the M-109 as the K-55 and there are differences.
Some things are trivial such as the K-9 having automatic turret lock as opposed to the K-55's manual turret lock.
There is also differences in the fire control system. I'm not a real arty guy so I can't really explain it but the K-55's fire control system is apparently more hands on as opposed to the K-9. This I have heard from artillery guys as well. The K-9's FCS is more advanced.
Actually, don't just take my word for it.
http://www.globalsecurity.org/military/world/rok/k9.htm
Globalsecurity.org claims that it's superior to the M-109A2 in just about every way.
Another source I read a bit for some tid bits:
http://koreadefence.net/print_paper.php?number=951
Though I don't think it'll help you much, it's all in Korean.

Originally Posted by the_13th_redneck

Actually no.
South Korea fields the M-109 as the K-55 and there are differences.
Some things are trivial such as the K-9 having automatic turret lock as opposed to the K-55's manual turret lock.
There is also differences in the fire control system. I'm not a real arty guy so I can't really explain it but the K-55's fire control system is apparently more hands on as opposed to the K-9. This I have heard from artillery guys as well. The K-9's FCS is more advanced.
Actually, don't just take my word for it.
http://www.globalsecurity.org/military/world/rok/k9.htm
Globalsecurity.org claims that it's superior to the M-109A2 in just about every way.
Another source I read a bit for some tid bits:
http://koreadefence.net/print_paper.php?number=951
Though I don't think it'll help you much, it's all in Korean.

13th, the US is currently using the M109A5 an M109A6;

Excerpt from the globalsecurity.org article on the M109A5/A6,

Paladin features include an Automatic Fire Control System with onboard ballistic computation and automatic weapon pointing, an integrated inertial navigation system with embedded Global Positioning System (GPS) processing, Nuclear, Biological and Chemical (NBC) protection with climate control, hydraulics system segregation, and secure voice and digital communications. Hull , turret, suspension and automotive upgrades significantly increase reliability, providing 40 percent greater operational availability than previous versions of the M109. On board, embedded electronic diagnostics improve maintenance and repair functions.

http://www.globalsecurity.org/milita...k/k9-specs.htm

By all comparison, the PZH 2000 takes the cake, with the K9 coming second and the M109A6 third.

Yep. I don't claim the K-9 to be the best SPH in the world but like I thought it is a bit better than the M-109 series SPH.