I have been recommended a upgrade from a IHI VF23 to a VF34 as best suiting my requirements.

Which are fairly simplistic :

1. Better Spool Rate
2. More response over rev range

Any alternatives anyone can think of that may help me out in finding a solution.

 

Well, I am no turbo expert, but generally you can't have quick spool up and high boost at high revs.

Many people here rate the vf23 as a good compromise.

What's your current spec?

Things that can improve spool up include:
Better Induction £200ish
Decat downpipe £200ish
Custom mapping £700ish
Free flow uppipe £100ish (smaller gains)
Ported Turbo £??? (smaller gains, done as part of hybriding)

Things that can improve top end breathing include:
Better induction £200ish
Free flowing exhaust system £400ish
Custom mapping £700ish
Hybrid Turbo £700ish to rework existing unit
Equal length headers £900ish

So you might find you can achieve what you want my other means. But I am sure you will be able to sell your VF23 no problem if you really want to change.

Cheers

Paul