M2 MK1 TVIS Diaphragm and Waxstat Valve (Replacements and fixes).

Hello all,
    The glorious MR2 MK1 is still my all time favourite MR2, but sadly there are a couple of items which I don't seem to be able to find anywhere?
 
The first is the "TVIS diaphragm"(this is the Toyota Vacuum Induction System).  Essentially it's a butterfly valve that sits in the middle of the air intake manifold and blocks or joins the 2 halves of the 4 pipe system together. By doing this you can achieve greater pickup at low speeds(eg at idle) and better performance at high speeds.  Here's an interesting read: http://www.billzilla.org/4agstock2.htm
 
Mine has got to the whistling stage and the only way I've read up on to fix it, is to cut it open, use some silicone to massage all the gaps and perform a repair that hopefully works.  My only issue with this method is that silicon can stick(particularly with humidity) and then your valve will not be functioning correctly.  Has anyone sourced a replacement, after market or re-production that will fix this issue?   One of the horrors on this one, is that the entire intake manifold had to be replaced to replace the valve if your were purchasing the part from Toyota(an option I would actually undertake except Toyota no longer sell it).
A solution that's not ideal is to leave it open permanently, pull off the hose that goes to the diaphragm and put a screw in the end of the air hose. While this does get rid of the noise, it's not really fixing the problem and allowing your MR2 to perform to maximum potential(well original condition operating then if you prefer).
If anyone knows, then please do share as I can't be the only MK1 owner out there with this problem.  I'm certain most of the cars actually being driven will be experiencing this one by now.
 
The other is the "Waxstat valve".  This is the one which a lot of people put in there own solenoid with a switch to solve.  It's the one that allows your engine to idle high (1700 to 2000 rpm) from a cold start, until it has warmed up, by which time the valve closes and allows the car to idle at it's normal 800rpm.  This valve allows smooth starting and seamless operation of the vehicle without getting stalling when the engine is cold.  It's both a nice feature and a slightly annoying feature.  On the one hand I don't like an engine running at that high a speed initially as it's best to idle engines low, wait for about 10 seconds(or if you have an MR2 like us, you wait until the oil level indicator is showing it's half way or high reading, indicating that oil is now suitably circulating around the engine) before you put the car in gear and drive off.  You will be amazed how many people do not do this and the result is increased engine wear that is completely unnessesary.
In short, I'm an all original man.  I like my car to remain in that original condition look.  Sure I can wire up a solenoid and stick a suitable stylish switch in the blank next to the coin holder but seriously I'd prefer not to and keep the original operation and look present.  Does anyone know where I might find a re-conditioned, re-production or aftermarket waxstat valve to fix this issue?  I'm sure this is another one that will be on the minds of other MK1 owners as well.
 
Thank you,
Sean.