The best thing I can advise is have a test drive of a 1.6 4/4 Sport and a Plus 4. On paper the 1.8 4/4 has more power and torque than the 1.6 that replaced it but the performance figures seem poorer. Not sure why that should be but you certainly do have to rev the 1.6 to get performance out of it and as I've found, the 4.11:1 axle ratio makes a difference.
I guess its also down to how much you want to spend, a Plus 4 with sports exhaust would be the option I'd go for but in my case I prefer the narrower 4/4 body....hmm......75th Anniversary 4/4 pops into my mind
