On the SVX and 2.5 there are three plastic covers to remove.  On my SVX you
must also slightly re-locate the power steering pump to reach one or two of
the retaining bolts.  With the covers off, carefully mark the relative
locations of the cam and crank drive gears.  Removing the old belt may
require removing one of the idler pulleys.

Once you have the belt off you may have to remove and "reset" the hydraulic
tensioner.  You will need a large vise to very slowly compress the piston
and insert a steel wire into the retaining holes in the piston cylinder
assembly.  With the piston retained you can install the drive belt, making
sure the cam drive gears and crank gear are in proper alignment.  Re-install
the idler and then release the tensioner.

A good way to ensure relative alignment is to mark the old toothed belt with
paint and place adjoining marks on the crank and cam pulleys.  This ensures
the same number of teeth offset in the belt.  Transfer the marks by counting
teeth in the new belt after you have the old one off.

After ~10K miles on a set of seals installed by a shop, the seals began to
leak copiously and had to be replaced again.  $$$.

p