"is the pirc a good 'win at all costs' system?"
in short, no (since you are specifically referring to playing as black against 1. e4).
playing the sicilian would be my suggestion. definitely has a good track record for black.
I'm pretty sure you can get a Pirc set-up, out of most White openings, not just 1.e4.
i'd still suggest sicilian since OP is speaking of playing against 1. e4 (isn't he?)
"is the pirc a good 'win at all costs' system?"
in short, no (since you are specifically referring to playing as black against 1. e4).
playing the sicilian would be my suggestion. definitely has a good track record for black.
I'm pretty sure you can get a Pirc set-up, out of most White openings, not just 1.e4.