IDF is considered more favourable for a street application over IDA, which people believe to be more 'racecar'. For that reason, you are unlikely to find performance parts to make the IDF work. Best bet might be to sell/trade the IDF44 for a IDA of similar, and then buy the normal intake manifold for that.

（via Reddit）

IDAはセッティング（のための分解）がめんどいのにゃ