OK so the trans I have is a ST300, original to the car.

I am still wanting to replace (upgrade) it, and am seriously considering it sooner rather than later.

I am undecided over TH350 and TH200-4R... I think it's down to the TH200-4R having a better launch and the overdrive for cruising... and whether the cost difference is worth that to me...

The TH200-4Rs I'm looking at: Bowtie, CK Perf or PATC.
All around the $1200 mark excluding a torque converter (and of course shipping which will likely be ~$700 at least plus import duties... means I'll pay ~£1500 for the trans minus the TC). The TH350 I can get a no-name rebuilt one in the UK including a torque converter for £770 with no shipping fees. Or (also in UK, but excluding the TC, and would also require a Chevy to BOP adapter plate) a TCI Streetfighter for £870 (I might have just made up my mind...

Now, my questions:

Money aside, the TH350 with a 6" tailhousing will be a drop-in replacement... whereas the TH200-4R requires a TH400 crossmember - does the different crossmember for the TH2004R still mount to the subframe in the same place?

The TH2004R would also require the rear end gears to be changed (I have a 2.56 ratio)... what about the TH350?

Am I misguided / overlooking any major issues?

Both would require a shift conversion... is it possible for either to be column shift?

Any help greatly appreciated