35K too fast? Ya think! Heck, assuming the Warhead runs well, you're looking at 35+ RPM on the 27K on an 11.1v LiPo, and 25 RPM for 7.4v.
In my opinion, both are unneeded here. The spring strengths you're dealing with here aren't enough to display a difference compared to a well-built setup using an ordinary ChiHai Neo. I mostly use brushless for times when I want to keep the original 18:1s in the gun, or when I want to build something that places a lot of stress on the motor (1.5J+ & 50 RPM+). For a snappy efficiency build, you don't need brushless to get amazing performance.
But, assuming you want to spend the money and send it...
I'd go T238 brushless over both options. The ASG is extremely overpriced, and a lot of techs (including myself) favor T238 over Warhead. T238 is cheaper, has had less QC issues, and in comparisons actually were much quieter and drew less current than Warhead.