[plt-scheme] PLT4 expectations

Hello all,

This was probably already mentioned but I've been away from the Scheme
world lately, given I've been busy with a C++ project.
The idea of PLT4 creating by default immutable pairs and the so, means
that it also opens the possibility for far more and better
optimizations in the compiler, right?
Will these be implemented or the change to immutable structures is
just to have cleaner, more understandable code?

Far from ignoring these issues, I need to say that having faster
compiled code generated from mzc would be excellent!

Cheers,
-- 
Paulo Jorge Matos - pocm at soton.ac.uk
http://www.personal.soton.ac.uk/pocm
PhD Student @ ECS
University of Southampton, UK
Sponsor ECS runners - Action against Hunger:
http://www.justgiving.com/ecsrunslikethewind