Turbos are more effecient
ECU's are much more defined
Injectors easier to control
More 98 available - remember back in GC8 days you were using 95 Ron.
Tuning has come a loooooooooong way.
I remember in 03/04 if you had a R33 and were making close to 300hp you HAD to budget for forged pistons and rods. Now guys make 500 on stock internals and go for 50 000km without an issue.