a 19j should have ample power for an 88" or even a 109, it'll not give you stellar performance though
i drove an old 90 (only the second i've ever driven) with 19j a couple of weeks ago for 7 or 8 miles from a cold start up to full running temperature, this included town traffic and about 5 or 6 miles of M6 in the 50mph limited section, it kept up with all traffic nicely and was a pleasant sounding engine at 50mph, remember a 90 is permanent 4x4 so sucks more power out of the engine so potentially in an 88" it should be more responsive
would i fit a 19j in one of my Series, yes without a doubt as 99% of the ones that were unreliable have now gone to make baked bean cans, the only thing that would stop me ...
is the 200tdi's that i already have under the bonnets