If your going for something that is 2 in 1 unit types. The Power Enterprise boost gauge/boost controller is a good one. But you can usually tuck a turbo timber anywhere, now a days they are so small (ie, Apexi units for example). So honeslty the only unit you should concern yourself with is the boost controller which usually will fit in the glove nicely.
Honestly it's best to find a unit you like and then figure out a place to stick it. Personally I like the Apexi AVCR (boost controller) the best along with a small hideable Apexi turbo timer. But hey what do I know.