Should I do a fresh install of PostGreSql?

I had to reinstall a Rails app onto a fresh OSX Snow Leopard installation.

I had a hair pulling session just trying to get the pg gem to install properly with Rails. First I installed PgSql 9 through this link. However, I started getting errors when trying to run bundle install:

Installing pg (0.10.0) with native extensions /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:529:in `rescue in block in build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

        /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/bin/ruby extconf.rb 
checking for pg_config... yes
Ruby cflags: " -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe"
MacOS X build: fixing architecture flags:
  finding flags common to both Ruby and PostgreSQL...

*** Your PostgreSQL installation doesn't seem to have an architecture in common with the running ruby interpreter (["ppc", "i386", "x86_64"] vs. [])
I'll continue anyway, but if it fails, try setting ARCHFLAGS.
  testing for architecture: "ppc"
  testing for architecture: "i386"
  testing for architecture: "x86_64"
checking for libpq-fe.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/Users/Chris/.rvm/rubies/ruby-1.9.2-p136/bin/ruby
    --with-pg
    --without-pg
    --with-pg-config
    --without-pg-config
    --with-pg-dir
    --without-pg-dir
    --with-pg-include
    --without-pg-include=${pg-dir}/include
    --with-pg-lib
    --without-pg-lib=${pg-dir}/lib
/Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:368:in `try_do': The complier failed to generate an executable file. (RuntimeError)
You have to install development tools first.
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:452:in `try_cpp'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:853:in `block in find_header'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:693:in `block in checking_for'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:280:in `block (2 levels) in postpone'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:280:in `block in postpone'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:254:in `open'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:276:in `postpone'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:692:in `checking_for'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/1.9.1/mkmf.rb:852:in `find_header'
    from extconf.rb:123:in `<main>'


Gem files will remain installed in /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/pg-0.10.0 for inspection.
Results logged to /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/pg-0.10.0/ext/gem_make.out
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:507:in `block in build_extensions'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:482:in `each'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:482:in `build_extensions'
    from /Users/Chris/.rvm/rubies/ruby-1.9.2-p136/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:156:in `install'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/source.rb:96:in `install'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/installer.rb:55:in `block in run'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `block in each'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `each'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `each'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/installer.rb:44:in `run'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/installer.rb:8:in `install'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/cli.rb:226:in `install'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/vendor/thor/task.rb:22:in `run'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/vendor/thor.rb:246:in `dispatch'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/lib/bundler/vendor/thor/base.rb:389:in `start'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/gems/bundler-1.0.10/bin/bundle:13:in `<top (required)>'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/bin/bundle:19:in `load'
    from /Users/Chris/.rvm/gems/ruby-1.9.2-p136/bin/bundle:19:in `<main>'

I came across this article, which suggests I install PgSql 8.3 via Mac Ports. So I did that, and followed the rest of the instructions in the article. I managed to bundle install and start the rails server via rails s without any problems.

My main concern, is that I believe I have 2 installations of PgSql. One is version 9 and the other version 8.3. Should I uninstall version 9 for whatever reason? Or does the latest installation override?

Or should I not worry about this? Second, I've searched everywhere for proper documentation on how to uninstall version 9 on a Mac OSX, to no avail.