[Avionics] GI106 compulsory with GNS530 ?

Hello,

We plan to overhaul the panel of our good old PA34 Seneca.
Unfortunately, the 2 workshops from whom we requested a quote disagree :
- one says the GNS530 we're buying can work with one of the 2 VOR/ILS
indicators currently in the plane (these are "KI something", one connected
to a KX165 and the other to a KX175B).
- the other mechanics asserts we have to buy the specific VOR/ILS indicator
from Garmin (GI 106A).

The additionnal cost is not that big (still a little more than 1K$ on a
total 30K overhaul), but I feel one of the 2 has to be wrong, and I'd rather
give this work to a competent guy.

Anybody faced this problem before when installing a GNS430 or 530 ? Is the
GI106A compulsory to function properly with it ?

Thx
--
YAG