The GOP doesn't need saving because it's not in trouble. As a cesspool of thieves and corrupters, it's thriving.
If you want to affect it or harm it (or "change" it), I think the Paul's are proving it is faster and more effective to do so from within. It took a confluence of events - primarily an already cultish-figure, freakishly re-elected Congressman running in the primary for President and thrown a bone by Guliani to establish a rallying point/leader - but it seems to me that Ron/Rand (stay tuned) are doing more to "dismantle" the GOP in the past five years than the Libertarian Party has done in forty.
To be clear - I do think the LP has a role and should continue pressing on. I'll certainly make my voice heard by voting for Johnson.