I have an 1991 MX83 Cressida... How easy is it to replace the standard engine with a 1JZ-GTE or the 7M-GTE? Which is better? Is there something else I should look at? My aim is too boost the power as cheaply as possible but not too much power so that I can keep the auto and other stuff standard. Also, what is the 7M-GE worth? I mean how much will it offset the cost of its replacement?