The way I'd do it is put the values in an array, process the array and print it with either $, or $" set to "\t".
BEGIN { $,="\t"; print "Head1".."Head4"; } @v = ("w", $F[2], $F[3], length($F[9])); $v[0] = "c" and $v[2]++ if $F[1] =~ /83/; v[1] =~ tr/ACF/BDG/; print @v if $F[1] =~ /99|83/;
Untested, since I didn't have input data :).

"Head1".."Head4" is a little bit of perl magic to print your headers. tr will replace every occurrence of the letters, not just the first like you did, but you get the idea.

Edit: removed useless slice on first definition of @v.

Edit: replaced all the $v{X} by $v[X]

Can you clarify "removed useless slice"? I know this is not a golf problem, but one liners are a place where brevity can be useful. As I see it:

@v = ("w", @F[2,3], length($F[9]))

is valid syntax and would save 5 characters.

But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. Romans 5:8 (NASB)

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would save 5 characters.

@v = ("w", @F[2,3], length($F[9]))
@v = ("w", @F[2,3], length $F[9])    # -1 more!
[download]

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
[download]

I started with @v{1,3} = (...) and a separate computation of $v[0] and $v[2]. But I turned that into @v{0,1,2,3} = (...), where the slice on @v is not only useless, but also incorrect now that I think of it (since it was actually a slice on %v). And yes the code can be shorter (there is a lot of unnecessary white space for example), but I was expecting TJCooper to adapt the oneliner to his needs anyway.

Great, thank you! That makes sense after i've adapted it.