One problem you may well encounter is that your wheels won't clear the 24v calipers. Whilst initially they looked the same the wheels from my 12v TE's foul the calipers on my 24v.
A new set of wheels will push the price of the conversion up appreciably.
90 300TE 24v (M104 eng) 207K miles
87 300TE (M103 eng) 269K miles (and never had the head off!)
86 300TE (M103 eng) 230K+ miles (donor car)
95 Toyota Lucida diesel 4wd
86 200T 165K miles (sold)