Conversion-Metro to RWD

[GottaQuestion]

I have recently acquired the bug to grab a used Metro for tinkering.

I am wondering which year model would be best and would allow modest conversions? I am looking to convert the metro to a Chevy 4.3L V-6 and rear wheel drive. This of course means making room for for a different trans and engine configuration and locating a rear axle Assy that would fit the Metro.
My first choice would be looking at either an older Vega or Chevette for their turbo tranny and rear axle. I have had both and found them to rather robust. The 4.3L I am finding can be off-the-shelf fitted with performance parts and hit the 300+ HP range, an option I think would be fun in the Geo class of car.

Any thoughts on the topic would be appreciated.

[lurker]

this is sort of like an idea i had, to move the stock tranny and motor into the back.

you might find it useful to look at the pontiac fiero, ( see http://www.fiero.nl ) which had a transverse front wheel drive train in the back, resulting in a rear-mid-engine configuration. fun to drive, ripe for modding. it came stock with either a 2.5L 4 cylinder or the 2.8L 6 cylinder(though ive seen engines from the 3.0 to the SBC put in them), automatic or manual 4 and 5 speed gearboxes. the only things i see as major hassles would be stretching the wiring harness, and shift linkages. probably need to beef up the rear suspension, too, unless youre planning to leave the engine in the front and put in a driveshaft.