With your combo and budget, I think the best answer is going to be a TA49 or TE44 with a Garret 63 housing. Either turbo can be spooled with a re-stalled D5 (I ran my TA49 with stock D5 converter, and it was OK). Either turbo will run nicely at 93-octane boost levels (say 17 psi) with the potential to run over 25 psi with race gas or alky. At those boost levels, 11's are easy, and high-10's have been achieved (although rarely). If you're going to spend the money for a new turbo, I would suggest one of these.
The TA49 is completely stock appearing. The TE44 is exactly the same except the compressor cover is not stock (slightly more efficient) and will require a different wastegate actuator bracket. You can usually find one of these close to your price range (used) in the "Parts For Sale" section, or you should consider spending a little more for a nicely rebuilt one from Bison.
Good Luck,