I'm about due for a drivetrain upgrade on my Cervelo P2c circa 2009 which hasn't had a crank change since then.

Actually, the REAL reason I want to upgrade the drivetrain is to specifically end the horror show of FD/RD internal cable routing on my Cervelo. Before you experts jump in at how easy internal cable routing is - this Cervelo is NOT so easy. The exit hole for the FD is so tiny that you can't even fit any adapter head of a Park Tool Internal Cable routing magnet kit into it, and you cannot even pass a minimal cable liner through it to lead the wire before you remove it. I've resorted to gluing a strong thread to the wire before I remove it, but even that is hit-or-miss as it comes off half the time.

Was thinking of doing eTap for wireless so I can avoid all the fuss, but am not sure how the battery/blipboxes would work with a bike that was never intended for wireless. Any other part swaps required, like new cockpit?

Di2 obviously is also considered, but I'll likely go with whatever is easier to install.

I also don't really have a preference for 1x vs 2x - I like the simplicity of 1x, and I'm not worried about running out of gears on hills.

Anyone who has advice on what to get, or who has done this upgrade themselves, please chime in!

-For newer AXS 12 speed etap...

The one tweak to the AXS options above is that you will probably need a new rear wheel and a compatible XDR freehub body.

Goddang cycling gets $$$$ quick. Change one thing, gotta change 'em all.....

Thanks everyone for all the helpful info. I'll have to see whether this is all actually worth it - I'm spending so much with this setup that it may be simplest/easiest to just buy a new TT bikes outright given I suspect it'll cost me personally the entire difference in terms of opportunity cost of my time spent researching/installing/troubleshooting in on my Cervelo p2c.

In the meanwhile, I def still adore my P2c - except for those darn holes! I will likely drill out the FD cabling hole, as it's so tiny.

I'm about due for a drivetrain upgrade on my Cervelo P2c circa 2009 which hasn't had a crank change since then.

Actually, the REAL reason I want to upgrade the drivetrain is to specifically end the horror show of FD/RD internal cable routing on my Cervelo. Before you experts jump in at how easy internal cable routing is - this Cervelo is NOT so easy. The exit hole for the FD is so tiny that you can't even fit any adapter head of a Park Tool Internal Cable routing magnet kit into it, and you cannot even pass a minimal cable liner through it to lead the wire before you remove it. I've resorted to gluing a strong thread to the wire before I remove it, but even that is hit-or-miss as it comes off half the time.

Was thinking of doing eTap for wireless so I can avoid all the fuss, but am not sure how the battery/blipboxes would work with a bike that was never intended for wireless. Any other part swaps required, like new cockpit?

Di2 obviously is also considered, but I'll likely go with whatever is easier to install.

I also don't really have a preference for 1x vs 2x - I like the simplicity of 1x, and I'm not worried about running out of gears on hills.

Anyone who has advice on what to get, or who has done this upgrade themselves, please chime in!

Goddang cycling gets $$$$ quick. Change one thing, gotta change 'em all.....

Thanks everyone for all the helpful info. I'll have to see whether this is all actually worth it - I'm spending so much with this setup that it may be simplest/easiest to just buy a new TT bikes outright given I suspect it'll cost me personally the entire difference in terms of opportunity cost of my time spent researching/installing/troubleshooting in on my Cervelo p2c.

In the meanwhile, I def still adore my P2c - except for those darn holes! I will likely drill out the FD cabling hole, as it's so tiny.

@jackattack: So you managed to get the old SRAM Red eTap before it was withdraw from the marked and replaced by 12speed AXS.