Hey, love the mod, tho I found few issues.
1) Krastorio adds balistics to weapons and such the poor engineer tends to shoot itself instead of biters. Not painful, just blocking the bullets.
Idea: Make smaller or remove hitboxes from legs ?

2) In MP, players that joined and left leave behind their spidertron behind, making that area unusable.
Idea: Tie spidetron to the player that spawned it.

3) Flamethrower. My guess is that you used tank flamethrower, so it won't leave fire on the ground. This is kinda making it pointless, because shotgun is somewhat more usable (more range, and possibly more damage), but I am not sure if you can add normal flamethrower to vehicles.
Idea: Change it for normal flamethrower, or option to change it into different weapon.

4) This is somewhat tied to 3). Mods that add more weapons, feel more or less useless. For example Krastorio adds sniper and impulse rifle.
Idea: This is probably just asking to add synergy support to Krastorio (which I kinda expected, since there is a statement, that these mods are comatible O=)), but making the weapon slots somewhat customizable, would be lovely.

These are my issues and ideas with the mod so far. I will add more info if need be.

Edit: 5) Considering tieing spidertron to the player is an option, transfering player modifiers to spidetron user would be also nice.

Thanks for the feedback!
1) Yeah, I noticed that with my Spidertron Weapon Switcher mod when I fired tank shells as well. Not sure if anything can be done about it, but I'll give it a go.
2) That's definitely a problem that I can and will fix
3) I hadn't considered that, I'll probably switch the type then
4) Yeah, I haven't done any balanced compatibility with any mods yet (I mentioned in the mod description that this is 'coming soon'). To be honest, it doesn't sound very fun to do (particularly because I haven't played any overhaul mods like SE, K2, BA etc), so I'll likely create a more versatile setup system first and then invite others to submit changes for a particular mod/modpack.
5) I'm not sure what you mean...

You are more than welcome. Always happy to help, especially with something I am interested in.
5th point was just a nieche thing, and since only vanilla modifer to the player is movement speed (bricks, concrete), it is mostly noticable with mods that add special modifiers to player characters.
It was meant this way: give the spidertron bonuses which are applied to the player, so if player get's bonus % to damage, give that effect to the spidertron.
But as I said, it's just something I would like to see, not actually need.
(Sorry for typos, it's kinda late and I ran out of coffee juice)

Oh ok, yeah I can look into doing that (though I'm not sure if it is actually possible to boost the spidertron's damage without reloading the whole game). Increasing its movement speed certainly isn't possible.