86rolla wrote:hey,
just wondering how much work involved and $$ to change from 20v silvertop to 4agze? and any modding to other things - ecu etc
cheers!

Wasting your time and money converting in my opinion.
It will be cheaper easier and better to turbo your 20V.
Buy some standard toyota GZE pistons and a head gasket.
Fit the to your engine with new rod bolts and head studs,
Get someone to make a manifold that suits your car and turbo choice,
Make an air box to replace the standard one that will hold pressure,
Run the standard wiring loom and all accessories like alt p/steer a/c etc as they are a pain otherwise,
and fit a aftermarket ECU in place of the std one.
that way you save on wiring, dont have to but a whole new motor,
dont have to shag aroung mounting things etc.
there are a few other small things to do aswell.
My guess would be $2000 minimum, up to $5000 depending on what items you choose to use, how much you get them for and how much you do yourself.
this is my opinion and i'm sure others will have other idea's.