user14319: Is there a maximum size for any given transaction?
I just created this tx: 
http://blockexplorer.com/testnet/tx/194173dcc07b396433d5725abe76d52b10d42ebd3d1d10b465429f87fee12a52 
and although it seems to get confirmed I would like to know if adding more inputs or outputs (and thus increasing its size) could result in an undesired outcome.
Similar question (that doesn't answer my question, though): What is the maximum size of a transaction?

user15524: There is a maximum standard transaction size since Bitcoin 0.8.2 of 100k per transaction.
There are a number of other limits that influence the validation and propagation of a transaction though. Specifically:

A block is limited to 20000 signature verifications.
The block itself can't be larger than 1Mb.
The standard Bitcoin client (Bitcoin Core / bitcoind) will refuse to relay transactions flagged as dust.
Enough fee should be included (0.0001 BTC/kb)


14319: <p>Is there a maximum size for any given transaction?</p>

<p>I just created this tx: </p>

<p><a href="http://blockexplorer.com/testnet/tx/194173dcc07b396433d5725abe76d52b10d42ebd3d1d10b465429f87fee12a52" rel="nofollow noreferrer">http://blockexplorer.com/testnet/tx/194173dcc07b396433d5725abe76d52b10d42ebd3d1d10b465429f87fee12a52</a> </p>

<p>and although it seems to get confirmed I would like to know if adding more inputs or outputs (and thus increasing its size) could result in an undesired outcome.</p>

<p>Similar question (that doesn't answer my question, though): <a href="https://bitcoin.stackexchange.com/questions/1823/what-is-the-maximum-size-of-a-transaction">What is the maximum size of a transaction?</a></p>
 15524: <p>There is a maximum standard transaction size since Bitcoin 0.8.2 of 100k per transaction.</p>

<p>There are a number of other limits that influence the validation and propagation of a transaction though. Specifically:</p>

<ul>
<li>A block is <a href="https://github.com/bitcoin/bitcoin/blob/master/src/main.h#L45" rel="nofollow">limited</a> to 20000 signature verifications.</li>
<li>The block itself can't be larger than 1Mb.</li>
<li>The standard Bitcoin client (Bitcoin Core / bitcoind) will refuse to relay transactions flagged as <a href="https://code.google.com/p/bitcoin-wallet/wiki/DustTransactions" rel="nofollow">dust</a>.</li>
<li>Enough fee should be included (0.0001 BTC/kb)</li>
</ul>
