Dun sa upuan... I'm not really one to complain about hard seats, as I find these give great support and are much more durable in the long run, especially if said seat is leather. Take our Revo's seats for example. Material is high grade moquette. Very softly upholstered too. Can make for a rather comfortable bed if I wanted. But my back starts complaining if the driving time exceeds an hour or so. The Accord's seats on the other hand are really hard. Its actually quite similar to the FD's seats. But then it gives excellent support even in long drives and still looks pretty much the same since the day it was bought.
SiR? Kung hindi ka naman kumakarera lagi, dun ka na sa ES. Sure the SiR has a hell of an engine, but it has no safety features whatsoever besides the 4 wheel disc brakes. Very scary if you ask me. Yung VTi-S variant ng ES meron nang ABS/EBD and airbags. Besides, it already has 130hp on tap, which is already very respectable for a 1.6L engine even by today's standards.
Pangit ang Nissan? Not necessarily. Parts for the Sentra are actually pretty widespread, since it is used for cab service.
A/T's have come a very long way since the 90s, but they are still inferior to manuals in terms of performance and fuel efficiency. Manuals are still much simpler, lighter and more durable. There are some modern manuals that use a dual mass flywheel though. These are quite expensive to replace and may be what your friend is referring to.
2002 Grandis? Wala pa atang Grandis nun dito ah. Converted ba yan? That one has the GDi engine, which would probably explain the good FC. The local Grandis is classified as a minivan, and is based off the Galant with the traditional MPI engine. Ride comfort and performance are good but FC should be just around 5-7km/L city.
Bat binebenta after just a short time? There are many possible reasons. Some dahil naaksidente o nabaha. Others dahil aalis na sila. Yung iba dahil hindi na bagay sa route nila (for example subcompact sedan then mining area ang workplace). Others still dahil lang nasawa na.

I know of people with deep pockets who would change their cars like they change cellphones.