TB-02 is a fantastic design, I like it.
(Its probably better than a TA04S even... more adjustable.)
But if you're going to hop it up with all the TB-02 options, you're
probably better off buying a good used TB Evo III instead.
My TB-02 has the alloy steering, alloy motor plate, SSG strip
and alloy spacers on the hingepins... and it runs on par with
my EvoIII and EvoIIISL - impossible to tell difference on track.
Ideally you'd upgrade the TB-02 shocks to TRFs and the diffs
to the EvoIII black ones too, plus EvoIII oneway front.
Once you do all that... just get an EvoIII.
EvoIV looks very nice, but the stock kit is far from complete.
The screws are steel, not every part is carbon fibre etc.
It is very expensive for what you get in the IV pizzabox
+ Tamiya just wants your $$ spent on options.
I'm still running EvoIIIs and am not tempted to go IV / 415.
Built correctly, my cars haven't stripped a oneway gear again,
especially with the update longer shafts & Tech 3-piece shaft.
Solid chassis but not overweight... imho best car from Tamiya.
They are easy to setup & they handle great on our tarmac.
I'd buy a good EvoIII Surikarn Ltd over a similarly priced EvoIV...