Welcome Jonathan!!

At 1m 88cm you'll be fine, My car has been driven by someone at 1m 93cm, it is possible to gain more space by extending the wheelbase or moving the pedal box into the engine compartment.

Most of the steel used is 16 guage which is around 1.6mm, the wishbones are seamless tube with a 2.5mm wall.

I'm sure someone on here is using that engine but my swiss cheese brain won't tell me who it is!

I'd ask on Locostbuilders http://www.locostbuilders.co.uk/index.php# too but it seems to be broken again at the moment.

Cheers

Chris