Where should I get it done and What should be done? Thanks.

- No Purchase Neccesary. Details Inside.

replace timing belt/tensioner/water pump.

This can be done at the dealer if you want to pay for it, 600 area

Other mechanics places can do it also and might be cheaper.

Or you can do it yourself http://www.vfaq.com/mods/timingbelt-2G-NT.html

1998 dodge avenger 4 cyl AT
Mods are:
Not enough

Ok, well I was gonna say "check the already seen forum"
http://www.2gnt.com/cgi-bin/dcforum/dcboard.cgi?az=list&forum=DCForumID36&conf=DCConfID9

BUT it's not there... closest thing is the UDP install... ADMINS? This is a huge topic, imo should be in there I'll scrounge up the old links if you want.