For a rev counter I went for the VDO, more expensive but better looking and a better match for the existing guages and very good quality.
I wouldn't bother with permanently installing a boost guage, it's only use is when inially setting up your boost. Once you know your maximum boost pressure it's not going to change. So I'd recommend buying a cheapy boost guage, set it up temporarily, get you max boost where you want it and then remove it.
Of much more use if you are performance tweaking is an EGT guage, if you don't have one a bit of research will reveal it's importance.
HTH
Mo