4000Q Chassis stiffness upgrade?

[Aerostich/Andy Goldfine <74544.323@compuserve.com>]

I have owned and enjoyed my 1985 4000Q for many years and I have two questions
about it that I hope someone here will be able to help me with.

1. The steering seems more sensative to road surface irregularities and cross
winds than it used to be.  The whole car seems "looser" and more of a
"flexi-flier" than it was, and it never has been a real stiff unit body to start
with. The struts, rack and other steering parts all seem OK.  Is there any type
of aftermarket brace sold that fits between the top of the strut towers and the
firewall that will make things a little tighter?  Or should I check out another
opinion on the suspension and steering parts first?  I think that I drive a
little harder than average. Not especially fast, but I like to toss the car
around. 

2.  Since the car recieved a new heater core a few months ago it sometimes seems
that sometimes there is very little heat avalable at low rpm's.  Sometimes there
is enough heat, sometimes there is not.  The water valve to the heater seems ok.
The thermostat is old, but tests ok.  Any suggestions? 

I have been a subscriber to this list for (I think) about a year, but do not
always have time to read each day's digest.  If you respond more than a week
from this date, please reply direct to me <A.Goldfine@genie.geis.com> if you
can.  

Thank You.