Toyota Repair: CAT CONVERTER RATTLE / 95 PREVIA LE SC, torch flame, muffler shop

Question
95 TOYOTA PREVIA LE SC  2 wheel drive ,  112000 original miles.



Q1 .
CAT CONVERTER RATTLE

Is it better to get a direct fit to replace front Cat Converter , or have the Muffler shop replace it with a generic equivalent after using an Acyteline gas torch flame to cut pipe on both sides ? Direct fit is much more expensive .. seen on line 3rd. party units for $250 - $295 for part alone  . ... Generic Cat replacement approx $150 incl. labor .

2. Same 1995 Toyota Previa LE SC .. ACCESSORY SHAFT VIBRATES ON IDLE ... Solution ? I think bushings are worn ?

3. Sliding door handle on passenger side broke off , when I tried to yank it open . ( Door was difficult to open sometimes )

4.  TRANSMISSION OIL DARK RED .

Is it better to just drain and fill with changing gasket and filter , OR flush @ 112000 miles ? Was Flushed at 80,000 miles previously . I heard flushing can cause metal flakes to lodge into areas which might cause more problems ?  

4. Advise Coolant drain and fill OR  Flush ?  

Answer
It's ok to have a muffler shop weld in new cats,check with the toyota dealer there are repair kits for some of these driveshaft bushing problems, if not available then the acc driveshaft has to be replaced. Just drain and refill the transmission at this time and hope for the best. It's obvious that the door handle needs to be replaced, it will require the removal of the inner door panel.