Some people never are happy with their power. Would you have more tuning options with an EVO engine? They are easier to get than the VR4's. I'll keep an eye out for you and let you know if anything comes up.
Yes a Evo 4/5/6 will fit with a bit of modding but from what I understand there is more work involved fitting an EVO that a VR4.
There is someone in our club who has a EVO powered FTO, being rebuilt at the mo, there are also 3 VR4 powered FTO's in the club. ONe just been on the rollers at 408atf, another one being built as I think I mentioned to you at the show that will be a monster. not sure what it will be running at.