I'd say it depends on what sort of driving you do... if mostly highway, yea... M410 would be nice. But....

Read below my post about rear end compatibility... Sounds like your auto equipped car would have some pretty tall gearing in the rear... 3.35ish or something, so even with just the 4 speed, it'd probably be fine.

And.. you can always add the M410 later.. the swap from auto to stick is by far the lion's share of the work..

As George mentioned, you would be best to be sure you have all the parts in line before you start.. pedal box if applicable, clutch and flywheel bits, driveshaft... Ideally, you'd have a complete donor car.

And, as George also mentioned... the RHD thing means that most of us won't be able to help a whole lot...

Were I you though... if you've got all the parts for sure.. I'd go with the M400 for now and see how you like it. Then swap trannys when you find one with overdrive.

--
-Matt I ♥ my ♂