I think you're right. :-) Time to try to find the short soft spring set.

Could you get me a part number?

This is what I have two sets of: Tamiya Hard On-Road Tuned Spring Set TAM53440

#53333 are the go-to set.

Is stuff entering the gear box a serious issue? I've been running my car on the track without covering the hole for 4 weekends and so far didn't notice things entering the gear box.

The plug design I like a lot though, should be great running in bashing surfaces. Does it pertudes out of the chassis bottom?

Had I built my car as stated in the manual with one piece of tape on the bottom of the chassis I would have destroyed my transmission gears by now. After the first or second run the bottom tape was completely gone. I also put tape on the inside during the build and a 1 to 1.5mm pebble was stuck to that piece of tape after a run. Had that gotten in the gears it wouldn't have been good.

Yes, the plug protrudes about 1mm off of the chassis. At this point I can't think of any way to plug the hole and still have it easily removable for access to the pinion screw. But you can easily sand that down to make it as thin as your liking. Obviously you will lose strength so discretion is advised.

Got my super shorty lipo today. It's so adorably tiny! Sticks out just enough on either side of the M07 "spine."

Also got a relatively giant (full size) servo for my buggy that I'm pretty sure weighs more than the battery.

Are you running foam blocks on either side to center the battery?

It appears that will be necessary. Either that, or find a way to tape it in.

all of the tape methods I can come up with seem to expose tape to the bottom of the chassis, or secure the battery to the top of the chassis. I'm not sure I like either. Perhaps carpet tape?

I have a super shorty I put in my DT02. It amazes me how long it runs for with that thing in there. I have a big stack of foam in the battery box to hold it up at the front of the chassis. Turns out that buggies like weight on the front end. Who'da known?

who makes these super shorty lipos? and just how much shorter are they than a 'normal' shorty pack?

They are the size of a typical 1 cell 1/12 scale pack

They're half the length of a normal pack, instead of 3/4.

I (thought) I sealed my M05 pretty good, yet everytime I opened it for servicing i'd find small bits of debris inside the gear box. I only drive my cars on prepped tracks, yet dirt and debris always seemed to find their way in. I get that the M07 is a bit different than the M05, however I think the plug is a cleaner looking solution than tape.

https://images.amain.com/images/large/ori/ori14081.jpg
similar to these:

I use one in my TCS F1 car (no weight limit) but I don't see them being advantageous in mini.

I ran a "rectangular" type of battery this past weekend at Jackson in my Mini for the first time and it seemed to fit better than the (I guess you'd call them) oval packs (?)
I did have better power to the motor also, but I think it was because I changed chargers and now seem to be charging abit better. The weight didn't change that much either, 1315 ( Rectangular) 1305 (oval),, Are these shorty rectangular packs heavier
than the other rectangular packs????

I've had good luck with using silly putty inside the chassis. There are a few spots that debris can get through, push the putty in there. Also, at the top outside, right under the steering rack too. No issues since. And some tape over the other four motor screw holes.