97 front end problems

my 97 2 door 3cyl is having some issues. 175k, 5spd.

Leaked oil like a sieve, replaced oil pan gasket - old one was perma tex! Fixed.

Clicking when I turn hard right (sometimes left) - I assume CVs

Front tires wear unevenly - inside edge, two spots through to the belts. Thought this was a bad tire, then the other side did the same thing. My mechanic said there was no camber/castor adjustment?

Sometimes there is a semi-violent shaking/vibration at high speed (55+). sometimes it is completely absent. Bearings?

When I changed the oil pan gasket, I noticed white/brown streaks in the underside of the engine. I am hoping this is water that came in from the Perma tex leaking.

No longer downshifts into 2nd gear. Grinds a little into third.

So I am planning on replacing the engine and tranny with a JDM and adding new axle half shafts (with CVs) all at once. Only problem - it doesn't seem that there are any 96+ engines. what gives? Could I use an earlier model with some modification?

Thanks,

Blake

The intermittant shaking has been going on for over two years and my mechanic has checked it out numerous times - Everything is fine! Nothing is bent, distorted, or otherwise obviously damaged. That's what I can't figure out. Of course it could be the cornfields I have been known to drive through.