You could try to make another OEM turbo work on your setup however all of those units will be internally wastgated, setup for their stock boost pressures. If you want an external gate those would make things a bit more complicated.
Personally, I like external gates so I would go with something like the Borg Warner SXE-252 with an .63 A/R. If you're willing to purchase right now, Boostlab has a sale on their own turbos which are basically garrett housings with their own billet wheels. They have a 5757 (57mm compressor inducer 57mm exhaust) on sale for $499, this is a journal bearing turbo so it would suit your power needs >(
http://www.theboostlab.com/bl-5757-turbocharger/).
I've personally also researched into a turbo for my M44 and to make about 400WHP the guys over at Boostlab suggested their 5855 ball bearing turbo. Bigger compressor wheel for more air flow and smaller exhaust wheel for faster spool plus the addition of being ball bearing compared to journal bearing. That unit is also on sale right now for around $800, but i'd only recommend that if you'd want to go for more than 300hp. You can find it here, all sale prices activiate in the shopping cart >(
http://www.theboostlab.com/bl-5855-d...-turbocharger/).