Culture vs. Galactic Empire, an interesting war?

[Axiomatic]

What sorts of limitations and unfavorable circumstances would you have to put the Culture under to make a war between it and the Galactic Empire actually interesting and not a foregone conclusion?

The only thing you CAN'T do is give the GE additional allies or technologies it doesn't already have, like saying "Oh, the Xeelee ally themselves with the Empire". What do you need to do to let the Empire meet the Culture on equal terms?

[Teebs]

The Culture could probably win simply by using their engine fields and braking very hard if I remember correctly, they're simply that mismatched.

[Darwin]

What do you need to do to let the Empire meet the Culture on equal terms?

A meddling godling to artificially cripple whatever Culture force you're putting up against the GE. Like, maybe they pissed off both the Time Lords and Xeelee simultaneously right before engaging the Empire, and had a real fight on their hands, ending up in the GE with all but their most essential systems disabled. Even then, they'd probably still ruin the GE's starfleet.

This matchup is like Clint Eastwood's Man With no Name vs Shoot-em-Up's Smith. Both undeniably badass, but a foregone conclusion without serious handicapping. Only one of them can wreck you with a fucking CARROT, much less a full arsenal.

[Axiomatic]

I know they're mismatched, that's why I'm asking how many hands the Culture needs to tie behind its back for the conclusion not to be foregone.

[18-Till-I-Die]

I know they're mismatched, that's why I'm asking how many hands the Culture needs to tie behind its back for the conclusion not to be foregone.

All of them?

Seriously that's what everyone is trying to say, this might as well be "A Kryptonian Green Lantern dual-wielding two BFG 10ks versus a wheelchair bound, blind hobbit with autism".

[Ghost Rider]

Been there, done that. The Culture is pretty much an out the wazoo power for the GE.