GT33 is a too small for IMAC, big is beautiful you know. Most IMAC guys fly DA80-100 or similar.
I know some IMAC style planes though.
There are some differences:
- No pipe but standard muffler is used. Generally noise reduction is not considered that important.
- Prop is smaller and with less pitch, quite common is 18x8 or 19x8 or even 19x6