HomemadeTurbo - DIY Turbo Forum - Compressor wheel size help

Hi,

Not sure if this is in the right forum but here goes and as I'm a newbie I hope this question isn't to stupid. I've been learning as much as possible about trim and wheel sizes but could really do with some advice.

I am looking to create a hybrid turbo for my V6 Saab which runs a TD04HL. Unfortunately we can't easily upgrade the turbine housing or wheel so I'm looking at potential compressor wheel upgrades.

20t - 47 ind 58 exd is a popular upgrade and known to run 400bhp
22t - 50.38 ind 68 exd seems to give too much lag and can run 430bhp

I'm looking for a wheel which outflows the 20t but doesn't introduce too much lag and I've narrowed it down to two options. I need some help and advice on the following compressor wheels, and what your thoughts are to the effects of each one.

50 ind 61 exd 6+6 blade
48.3 ind 68 exd 6+6 blade

Both of these will be run on the same 9 blade turbine wheel

What do you all think to the above specs? Which should spool quickest and which should flow best.

On these engines we really struggle with holding power over 5500rpm so it'd be great for it to hold power all the way to over 6000rpm.

Thanks in advance