What do you need done? While I've never used them, Concours Motorsports in Colorado Springs are a BOE partner. I know that 3R and SCR (the two other big race shops along the Front Range) have both seen Elises and Exiges in the past but don't specialize in them. Ferrari of Denver are a factory dealer and I haven't heard anything bad about them in the last few years although they are very expensive. I took my car there for the oil line recall and they seemed quite competent.
Most of the owners I know along the front range either DIY completely or ship their cars to BOE (by Kansas City) for major work.